My
What you do now is of paramount importance.
I'd prolly drop the night classes for now.
Find a way to hire an attorney that will take the legal steps required and in your interest (and childrens). You need to document the abandonment of the children ASAP IMO. Ask family for money or sell something. Most attorneys will talk to ya for atleast a few minuets for free. Tell them the situation and see if a course of action doesn't fallout of a conversation. If one attorney isn't in or plain won't help, call another and another until you have something to go on. If they can't help, ask if they know a local organization that can.
Just on principle, she needs to pay child support.
Wish you the best