Starting out as a pro

So I've been toying around with the idea of becoming a professional photographer. I'm on the verge (sorry for that) of turning 18, and it's the first career idea I've ever had. Currently I have a 500D with some lenses, no off body lighting and no idea how to begin.

From what I understand I need to step up my glass, my lighting and get some sort of website going. Maybe even upgrade my body. I think it's also a nice move to contact an established pro, and ask if I can become that person's apprentice or something like that.

I have grown a bit of experience of shooting models, but all have been with ambient light. So far, I know nothing of off-camera lighting.

Also, I'm nothing of a business man, so how to get my name out there is beyond me.

How do I start out? What's the best place to begin? What gear do I need to get? What would be a nice amount of starting money? Basically, I'm searching for a walkthrough on becoming a pro.