Depends what State you are in? There are I believe 7 non-recourse states (don't know them all), which if you are in one of the states you are not liable for the difference between the balance and what the bank is able to sell the house for.
I believe you could also walk away and file BK, and still be alright. It's a financial decision, and if you are saying you have little money, i'd give BofA a half peace sign and walk.