Save my home!! Urgent?

I am 5 months behind on mortgage. I have been in process of refinance for awhile and having a hard time with that. Credit score is 500 I have great income. Wife stays home. 3 kids ages 8,4,2 I am scared to death here. I have a co-signer available with a credit score in the 700's if needed. What can I do? I am desperate. PLEASE HELP!!!