I don't think that would make a difference for you - although it hasn't been fully explained. It will probably be OK, as I'm pretty sure it will be a credit on your 2009 taxes, which you won't file for, until this time next year, anyway.
Some people are making it sound as if it is a $7500-15,000. cash grant, that you could use to supplement your down payment.
I don't see it that way, at all. From what I understand it will just be a "tax credit" that you can use as a writeoff or deduction, to reduce your tax obligation. I may be incorrect - taxes are not my main business.
Good luck in your new house!