You'll want to go to the Family Court Facilitator at your county courthouse if you are self-represented, as that is a free service with an attorney to advise you how to go forward.
There is no "legal separation" in California as a step towards divorce. You can file for divorce or you can file for a judgment of legal separation. If you file for a legal separation, it is fully like a divorce except that the status of the marriage stays intact--- in other words, you are still married when the judgment is made.
If you do file, you will want to go to the Department of Child Support Services in your county- they can help you with both setting support and collecting support.
Answered on Dec 30th, 2013 at 3:33 PM