“I need a vasectomy?”

I've gotten on and off again positive results for syphilis after being in prison. My wife got treated for it out of caution- I did too. I just need a vasectomy so this girl I'm living with who isn't my wife, can't get pregnant and trap me. I already have 3 kids I don't have anything to do with. I am a convicted felon, drug addict, and have bipolar disorder and other mental disorders. I don't need any more kids. How fast can I get this done? I think I might still have insurance through my work but not sure. I'm pretty much broke and live in a shed with this girl.