The Washington Times has a story quoting Rosemary Jenks ( “If there is anyone left in the world, we would accept another 325,000 through the guest-worker program in the first year.” ) and [1] Robert Rector of the Heritage Foundation.

Mr. Rector estimates that the Senate bill would grant citizenship to between 9 million and 10 million illegal aliens. If allowed to become citizens, those immigrants would be permitted to bring their entire extended family, including any elderly parents.
“The long-term cost of government benefits to the parents of 10 million recipients of amnesty could be $30 billion per year or more,” Mr. Rector said. “In the long run, the [Hagel-Martinez] bill, if enacted, would be the largest expansion of the welfare state in 35 years.” [[2] Reform bill to double immigration,By Charles Hurt , Washington Times, May 15, 2006]

You can read the details of Rector’s research [3] here.