I'm no expert at this yet except to say read up on the 180, which I have not yet mastered myself!
Someone will be along with good advice.
Wait for The Lord; be strong and take heart, wait for The Lord.
I understand you said you don't have the money for the attorney, but could you go through mediation and have a child support agreement drawn up? I least it would be a start.
Sending you (((hugs))) and strength to get through this.