I need advice on car loan and divorce?

Ok so I got married a few years ago before I left for boot camp basically for financial reasons....I got a car in my name because my husband could with his credit but he is a co-signer on the paper work..... at the time of the car purchase we were not married but they filled the paper work out as married and used her last name as mine with is also false cause we never changed names.....well we are in the process of a divorce and I do not want to be responsible for this car anymore I have been making the payments since the car was purchased...at 1st I sent her the money and she never made the payments which had the car repoed but we got it out and I have been directly paying the payments ever since since she got the car repoed and is messing up my perfect credit. so I want either her to take over the car since its hers b ut her cedit is bad or them give me the car and ill sell it I dont want my cerdit messed up anymore and they are telling me I cant take her name off we were not married at the time of the purchase so the doentation is technically wrong but the dealer is no longer in biz and GMAC is trying to say we both have to sign on it and its my prob any advice I hope this makes sense