My ex filed paternity and support, what if I want...?

My ex filed a paternity and support movement with the courts. I was in the process of doing a paternity, support, and custody movement. Since she already petitioned me for support and paternity how can I petition her for custody? It seems that the paperwork says I can only file for custody if there is an order already saying I am the father. I am worried she is going to try and leave state before the order comes into place. She is trying to alienate me from my son and it is really worrying me. I have helped in the past but of course like a lot of vindictive people she wants more than that. Only reason I haven't filed for paternity earlier is because I was hoping she'd cool down and realize what she is doing but she hasn't. Now she told me she is moving within the next two months. It isn't fair at all and was wondering if there was a way I can file for custody without her moving.