In addition, funding for the bank-rescue plan is unlikely to exceed the $350 billion currently available under the TARP, another source said.

"We don't know yet whether we're going to need additional money or how much additional money we'll need until we see how successful we are at restoring a level of confidence in the marketplace," President Obama said in a news conference Monday night.

A Treasury Department source said the plan was essentially complete with only minor “tweaks” being applied. The plan is being presented to members of Congress this evening, according to sources.

Based on details coming out that presentation, the plan calls for:

Some $100 billion will be committed to new capital injections

Another $100 billion will go to the Federal Reserve's TALF program

And $50-100 billion on housing measures, as expected, according to the source

The package will be unveiled Tuesday by Treasury Secretary Timothy Geithner at 11 am EST. CNBC.com will carry the speech live.

CNBC will also interview Geithner after the speech at 12 Noon EST. It will be his first television interview since becoming Treasury Secretary

There’s been great speculation in recent days about both the measures and terms involved in the bank-rescue plan. In particular, there’s been great uncertainty about the inclusion of the "bad bank" concept, where the government would set up an aggregate bank and buy up billions of dollars of bad debt from banks.

For Investors

At the moment, the idea of involving private capital in the purchase of bad assets “is gaining speed,” said the source, who is familiar with the discussions. In that way, the government might simply encourage firms to buy the assets or provide some sort government subsidy covering some of the costs.

“You don’t need as many dollars," the source explained, and “the market sets the price.” Such a model would also reduce the likelihood of bank nationalization by demonstrating that the “company is strong enough to attract private capital."