Sorry about the problems. It seems like every few days there is a question from someone who, unfortunately, co-signed an agreement. A co-signer is directly liable for the debt even if they received no benefit from the transaction. This is an issue of contract and in most cases the only way to be removed from the contract is by lender consent. Naturally, the lender has little to no reason to approve this request since it eliminates one way for them to get repayment on the debt.
You will need to contact a local attorney and provide them the relevant documents to see what options are available. Good luck.
DISCLAIMER—This answer is for informational purposes only and discusses general legal principles, trends, and considerations and is not intended as specific legal advice regarding your question. This answer does not establish an attorney-client relationship.
Robert is right. You need to talk to a local Consumer Law attorney in your state who deals with this kind of case. It might cost a little but the peace of mind is probably worth it. Call your local attorney's Bar Association and ask for a referral to a Consumer Law attorney near you or you can go to this web site page for a Free Online 50 State National List of Consumer Law Lawyers (http://www.ohiolemonlaw.com/ocll-site/ocll-locate_local.shtml) and find one near you (lawyers don’t pay to get listed here and most of them are members of the only national association for Consumer Law lawyers, NACA.net). But act quickly because for every legal right you have, there is only a limited amount of time to actually file a lawsuit in court or your rights expire (it's called the statute of limitations), so don't waste your time getting to a Consumer Law attorney and finding out what your rights are.