Man this is a tough one. It almost makes you wish you put 0 down and when the bet (I say bet but it wasnt one for u i know) goes south you could have bought one cheaper and then send in the keys. I feel for you on this one and have no right answers. If the value drops to 300k then do what I wrote above. Other than that I would probably hold and not dump my down unless it tanked further to benefit you due to the shortage of income.
Best of luck
