OP--my advice is to do anything you can to keep the house (or sell it for what you owe). Rent it out, get roomates, use the 401K, sell things on ebay, etc. Also, do not limit yourself to location while looking for a new job in this economy. Okay, maybe you do not wantto move overseas as a single mother but at least be willing to go pretty much anywhere in the USA right now. You may be able to keep up the mortgage and still get a small place (apartment) where your new job is on your salary until the house sells. Once the economy is better and you are stable you can look for something in the specific location you want to be in. In the meantime relaize that teaching your son to work hard and honor your commitments even when it means sacrificing in the lon grun IS being a good mother. You can remember that when you feel badly about not being able to afford a bigger place, or the cool shoes, etc. BTW I am not flaming you for thinking about it. It is the financial advice you have been given and you are just trying to wrok through and figure out what is best. It happens that I do not think it is good advice.
Take in roommates. Dip into that 401k. Go back to court, say that the situation has changed drastically and ask for an adjustment. This isn't some disaster like a sudden illness this is someone looking to bail as a financial option. That should be a desperate last resort not a result of financial planning.
While this poster was awfully harsh in their first post's choice of words, I do agree with the overall meaning of what they say. Persoanlly, I wish the laws would change to be that you can never just be finsiehd with an unpaid debt. I think you should be able to have harrassing calls stopped and get a temporary hold on all debts (icluding not incurring additional interest) to get back on your feet in situations which would currently be allowed to file bankrupcy, but once you are on your feet again I feel you should have to repay those debts no matter how old they are. I think we would see much less reckless spending in our country if the law worked that way I am not saying OP spent reckalessly. Her mairragie fell apart

and her job disappeared and you can only plan for so many catastrophes. This is where I think the law should allow people to file for some sort of temporary halt to paying some of their bills while they find a new job, lease the house, get roomates, etc, but once they do, they should be required to pay say 120% of the bill every month until they have repaid what they did not pay while things were on hold, rather than just getting to pretend nothing happened and let the tax payers cover that time period).
DH's pay was cut by 20% a little over 2 years ago and he had to start commuting to a differnt plant about an hour a day (meaning our bills for gas went way up at the same time). THEN that plant closed down and there were no jobs around. He finally found a good job (my work does not pay much, his salary is really what we rely on)--in Germany. Yep, to have a good paying job in his field we had to be willing to relocate anywhere and we did. As it turns out we are very happy to be here and enjoy it, but we would have done it regardless (pretty much to anywhere not deemed unsafe for American families to live by our own government). In the meantime, unable to sell our house in the current market we have rented. The first 8 months were a nightmare of bad tenants, eviction, etc (all the while eating up a good chunk of our 401K--but not as much as it could have becuase we got a tiny place here until we could get that straightened out and did not do anything "fun" when we could not make all the payments out of the paycheck). We kept at it and finally have good tenants (and won a lawsuit against the first ones yesterady

, though I don't know if we will ever be able to get the money). It was not easy by any strech.
My point is that I have sort of been there (not in a divorce situation but with the no job and house payments and cannot sell the house sense) and I still feel that it is wrong to declare bankrupcy or walk away from the house unless you have 100% exhausted all other means. I honestly could not live with myself if I did and I would not want to set that example for my children.