To get the other $1500 you must have taxable income after deductions and exemptions resulting in a tax liability of at least $1500 for the non refundable portion of the American Opportunity Credit to offset. The $1000 portion is refundable meaning you don't need to offset it with a tax liability to get it. Did you have a tax liability on line 44 of form 1040 orline 28 of form 1040A?
