AN Adelaide family has made a personal appeal to US President Barack Obama to release their daughter from a prison where she is serving time for stealing food stamps from the US Government.

The single mother of two young has spent the past year in jail after the FBI arrested her for using a false social security number to try and obtain food stamps so she could feed her two young daughters.

Louise Early's family, in Adelaide's south, say she was homeless and driven to desperation after her seven-year marriage to Eugene Early, a US marine, broke down and he failed to apply for her to become a citizen.

The Australian Foreign Affairs Department then botched her passport application for more than six months so she could not bring the girls home, during which time she was arrested.

Ms Early's visually impaired mother Jenny Smith, 62, of Hackham said she had brought her two grandchildren home from Baltimore last February but now feared Louise's multiple medical problems meant she would not make it home.

The girls, Jenae 8 and Kaylea 7, are living with Jenny and their grandfather John, are attending an Adelaide school and have pleaded for the safe return of their mother.

Their house in Hackham is adorned with family photographs, messages of love and support and mementos of their lives in the US and here.

"The first thing I will do when I get mum back is give her lots of hugs and cuddles and never let her out of my sight again,'' Jenae told the Sunday Mail.

"The last time I saw her (December 2012) was in jail and there was a glass window so I couldn't hug her and we could only talk to her on a phone.''

Kaylea said: "I just want to play Barbie dolls with her and show her my (play doll) castle I got for Christmas''.

Letters shown to the Sunday Mail by Ms Early's family reveal how the 37-year-old has struggled with the overcrowded conditions and lack of medication, but hopes to return to Adelaide soon.

"I know I will be bringing home a new perspective, patience and purpose when I get out of here,'' she wrote in February to her aunt Nancy Iversen.

"I can never repay them for what they have done.

"All I can do is love them and support them when I get home and help as much as I can. I can't wait to get home and ease the burden off mum and dad so they can enjoy just being grandparents again.''

The family talk to and email Ms Early regularly but prison has exacerbated her bipolar disorder, she suffers epilepsy and doctors have told her she may need a pacemaker to correct a heart condition.

Ms Early is in a low-security Federal women's prison in Aliceville, Alabama and also spent time in the Federal prison in Danberry Connecticut.

She was first jailed at the maximum security Chesapeake Detention Facility in Baltimore, where she shared a dorm with up to 120 women.

Her parents have appealed to Mr Obama to expedite a so called "treaty transfer'' with the Australian Government so she can serve out the remaining nine months of a two-year jail term in an Adelaide prison.

"We are not even asking for her to spend less time in jail, although the two-year penalty is over the top, we just want her back here so the children can visit,'' Mrs Smith said.

Ms Early married Eugene in Hawaii in 2002 after meeting through mutual friends she knew from a school exchange program to Australia.

She was divorced in 2009, but then struggled in the economically depressed city of Baltimore to support her two children who are US and Australian citizens by birth.

Without her own US citizenship - which under military rules should have been completed by her husband - Ms Early struggled to care for her girls and battled with the Foreign Affairs Department for more than six months to get them passports.

Her passort had lapsed and she became an "illegal alien" living in one of the most crime-riddled areas of the US with two young children.

"She couldn't even apply for her children to obtain their food stamps which they were entitled to as US citizens because she was not," Mrs Smith said.

"She was desperate, homeless and made a silly decision to use someone else's social security number. It was a desperate attempt to feed the two children.''

Ms Early's parents gave her $7000 for a deposit on a house in Baltimore while she waited for the Australian passports and homeschooled the children because of the gang violence at the local primary school.

A letter on behalf of the then Foreign Affairs Minister Bob Carr, dated 22 January 2013 and sighted by the Sunday Mail, acknowledges his department botched the passport applications for Jenae and Kayla for more than six months, between June 2012 and January 2013 which worsened Louise's situation as she struggled to feed and house the girls.

A month before DFAT finally acted Ms Early was jailed awaiting trial as a "flight risk" in a so-called "supermax'' prison in Baltimore, after an informant told the FBI of her fraud.

Ms Early faced a 5-year jail sentence before being "pressured" into pleading guilty of "aggravated fraud'' against the US and had the penalty reduced to two years.

For the same offence in Australia, court statistics show offenders are almost never jailed, even though the maximum penalty is 12 months.

In November, Mount Gambier Magistrates Court sentenced single mother of one, Rebecca Jayne Bell, 31, to a three-month suspended sentence for being overpaid a much larger social security sum of $22,000.

Senator for South Australia Nick Xenophon has been lobbying Attorney-General George Brandis since November for Ms Early's release based on the ill-effects of her incarceration on her two Australian daughters.

The Attorney-General's department would not comment on the case, but Senator Xenophon said he would be appealing to Mr Obama, who has refused to respond to the family, for clemency based on the suffering of Jenae and Kaylea and Ms Early's own health conditions.

"This is a clear cut case of a silly mistake, a flawed legal system and two young children who are suffering because of it,'' he said.

Ms Early's prison term ends in September but she can be kept for another three months by immigration authorities.