(CNN) -- More than 17,000 women and girls from Nepal become sex slaves every year. Many end up in India, China or other Southeast Asian countries, and roughly half of them are children.

Anuradha Koirala -- the 2010 CNN Hero of the Year -- has been fighting to end this sex trafficking for nearly two decades. Since 1993, she and her organization, Maiti Nepal, have helped rescue and rehabilitate more than 12,000 women and girls.

Recently, Koirala partnered with actress Demi Moore on "Nepal's Stolen Children: A CNN Freedom Project Documentary." For the film, which premieres Sunday at 8 p.m. ET, Moore traveled to Nepal to meet Koirala and some of the people rescued by her group.

CNN's Kathleen Toner recently spoke with Koirala, 62, about how her life has changed since being honored as Hero of the Year and what work remains to be done.

Kathleen Toner: How did you feel when you were named Hero of the Year in November?

Anuradha Koirala: There were so many other people doing very good things who were being honored, so I wasn't expecting it. I was shocked.

I first thought of all of my girls at Maiti Nepal. I wished I was in front of them. I wished I was in my country. But I knew it was a chance to draw attention to the problem of sex trafficking.

When I returned home, they had a big rally with thousands of youths. I realized that the whole country was eager to work hard to make Nepal trafficking-free. It was wonderful.

Toner: How have things changed for you?

Koirala: I now feel that there is extra responsibility on me. I feel I must be even more committed since people around the globe are depending on me. I need to work even harder to get to the end.

We are working so hard. Our work is the same as before ... but (we want) to monitor more of the border crossings. The border with Tibet is a very important area. ... It's very difficult. People easily take a one-day pass to go across to Nepal, and no one monitors. We've found many girls being taken across the border and being used in different entertainment sectors and brothels, so now (we're considering) working there.

At this point, the most important thing we have to do is surveillance and stop, stop, stop girls from being exploited.

Toner: What was it like to work with Demi Moore on "Nepal's Stolen Children"?

Koirala: She was superb. I have seen artists, film stars, musicians and all kinds of celebrities, but often they look very snobbish, very superior. She was very down-to-Earth. She knew the issue and was really committed.

When we were working on the documentary, we had to go to the home of a girl who'd been trafficked, but it was very difficult. Her village was in the mountains, and her home was on a very steep hill. It was a very hard walk for half an hour.

(Moore) is very determined (to help). When she came to Maiti and met the girls, she was so good with the children. She really is committed to this issue. If more people like her come into this field, then maybe we will succeed someday.

Toner: What do people need to know about this issue?

Koirala: This problem of trafficking children and women needs to be addressed, because HIV and trafficking are synonymous with each other. The fundamental human rights of the girl child are being seriously violated. It is a heinous crime, and it harms the girls physically and psychologically. It's also increasing the transmission of HIV to a larger population.

We have to make more awareness, and everyone should be involved: NGOs, government ministries, police, media, community activists and the entire community. (We) can't reach every affected individual; families and communities need to be assisted and encouraged to take responsibility. ... At the end, the whole theme is sensitizing and increasing awareness of the public on a large scale.

Toner: It's such a widespread problem. Do you think that you are making progress?

Koirala: Yes. If not, I would not have been chosen (as CNN Hero of the Year). But more sensitizing and awareness is needed.

Nothing is impossible if the whole world collaborates. If CNN supports us, if the U.S. government supports us, if all of the world supports us, why can't we (end sex trafficking)? But I think I have to live also for another 20 years.

See the full story on CNN Hero Anuradha Koirala:

Rescuing girls from sex slavery