BINGO...I think we have a winner here...One more thing to note that no one else has pointed out.
You are requesting a "fast reply" in this thread as though you intend to buy the car soon and claim it on your 2013 taxes. You cannot do this. If you buy the car now, you will have to wait until you do your 2014 taxes to realize the benefit.
If you are 100% certain you will qualify for the whole credit, you may consider adjusting your withholding in the meantime. This will lower or eliminate entirely your return next year, but you'll be taking home the credit now over the course of the year instead. This can be risky, if you've miscalculated your estimated liability, or lose your source of income, you could wind up owing.