HELP HELP...TAX REFUND ON A NEW HOUSE WITH TWO UNMARRIED PEOPLE. DO WE CLAIM THE FIRST-TIME HOME BUYERS CREDIT?

I am currently closing on a newly purchased home, and my co-signer is my girl friend therefore her name is on the contract with the lender and as the owner of the house with me. We are not married and will not be for at least 5years. Based on the first-time home buyers $8,000 credit, do we file separately and claim the money each or just on mine as the sole of the contract? HELP PLZ