Here's a possible solution to keep your car: get a short term fixed loan - say 3 or 5 yr fixed. The rates are less than a 30 yr fixed and may give you enough of a break on your anticipated monthly mortage payment to be able to afford to keep the car. Here's another option: I was a little 'tight' myself on a new purchase in June and used an 'option' loan - it allows you to choose from four different payment amounts each month - it'll save you a ton each month compared to a typical 30 yr fixed - aside from being a mortgage broker, I own an '83 and I only wish my car was as stellar as your car is - and there ain't no way I'm sellin less its for a 930! call me if I can help!
www.aaaLoanSource.com (by the way, my 30 yr fixed rate today is 5.5%) GOOD LUCK!