Should I file for custody or visitation rights?

I have a 5 yr old son with an ex girlfriend,she lives in california and i live in arizona.I send her money every week to help support my child but she does not let me see or talk to him and if i dont send money she threatens me saying that she is going to have the courts take my rights away and that i will never see my son again.She also lies to me about how much money she needs so that i will send her more.I want to get joint custody or at least visitation rights so that she can not keep him from me or threaten me anymore.I also want a child support order so that she cant try to get more money out of me but i dont want to be paying half of my income to her because i have a family at home to raise.Should i file for custody or have a child support order put into place?