A GOP poll earlier this month had her behind by 11 points, while her own recent internal poll shows her now up by 2. The truth probably lies in the middle somewhere: the race is probably close even if she's not yet in fact in the lead, and she has probably gained ground over the past month.
She's struggling to hold onto her House seat mainly because of her Yes vote for healthcare reform. Her opponent is a bit of an nutcase, who believes that the 17th amendment, which calls for the direct election of U.S. Senators, ought to be repealed.