I seem to be getting further and further behind because my rate keeps increasing

I live in North Carolina. The house in question is my home in New Smyrna Beach Florida. I have an ARM which I obtained two years ago. I intended to have the home sold within l8 months after getting the ARM and I needed cash due to family situations. The buyer failed to follow through, the housing market in Florida went bad, and I now have a home with a loan that is more than the realtors value the house. I am not in default on my loan but it is taking every dime I have - including my savings to maintain payments - and other unsecured debt is going up because of this situation. I have attempted to seek information from GMAC regarding what I can do, but they have not talked with me saying that there is prepayment penalty involved, the house is worth less than my loan and my debt/income ratio is bad (these things I knew since I made the bad judgment of getting an ARM in the first place! - they sent me instead a payoff amount which included a prepayment penalty. It appears that I have to keep the loan to avoid a prepayment penalty while the amount of the loan continues to grow and the house value continues to drop. I would like some help.I would prefer to keep the house if I could get a loan that I can reasonably pay. I now have the house rented just to try to get some help in making these payments and I may be able to sell, but with the current market I can't get a price for this house that equals the ever increasing loan value.