First off congratulations on leaving an abuser that was the hard part.
Next will not be easy but you need to do it soon.
Go to DSS get the ball rolling for child support.
Apply for any public assistance for which you qualify
Get a lawyer.
Record any calls, Save any voice mails/emails etc. (if you print any emails be sure to print headers which will show the IP address of the sending mail server).
Never meet him anyplace that is not public, busy, and well lighted.
Take someone with you when you go.
Also you did not say if you were married IF you were file for alimony the fact you left is mitigated by his beating you. Also file for Equitable Distribution if there are any maritable assets. Also if you are married DO NOT DATE or see anyone doing so will hurt your case.
When he threatens you or the child (and he will slimeballs do not change) file a complaint and PRESS charges.
Do what you can to provide a stable, clean, nurturing environment for your child and the courts will take that into account. But the guide line is “best interest of the child”
Did I say get a lawyer??? well do it.