I am assuming you purchased this vehicle as a new (never been titled) vehicle. Go to www.irs.gov;
use the search feature to find IRS Form 8936. That is the form you use to claim the credit. The maximum credit is $7,500. In order to take full advantage of the credit, you must have a tax liability (see line 46 of your 2012 Form 1040 tax return). If the number on that line is $7,500 or greater, you get the full credit. If the number is less than $7,500, you get that number as the credit. The credit is a "non-refundable" credit.