hi i am here to ask a few questions to see if anyone can possibly help me

ok i recently split with my sons father, he told me to take our son and get out, now i lived in iowa with him, and im originally from pa, so i stayed in a homeless (domestic abuse) shelter for 4 days prior to arriving back in pa to my mothers house. yes there has been abuse in the relationship. now that i am back in pa, his father wants custody of him, so he filed a petition for custody, and since iowa has home state advantage, i have to go back to iowa for the case. now my questions are... his father has his birth certificate, i know i can apply online for one, but right at the moment all my spare money is consumed in lawyer fees and cannot afford to get him a birth certificate.. how can i go about getting him insurance thru the state of pennsylvania without it. my second question is, the only thing he has against me is leaving the state with our child, even tho he told me to take him and leave. after he was charged with domestic abuse, i gained full custody of my son, dont i have the right to take my son with me? i know that he cannot prove that i am unfit as since my son was born, i was the sole provider and caretaker of my son, he did nothing with him, he wouldnt change a diaper, hold him, feed him, give him a bath... i did everything. my sons father was so consumed in the internet to even spend 5 minutes with my son. is there anyway i can use that against him? if anyone has any answers, please let me know as the custody case is on march 11th.... i am also looking for some help on writing a 5-10 page affadavit if anyone could give me some ideas on how to go about that, thank you