I paint cars for a living (amomgst other things) the very last thing I would want, is to paint on top of someones botched self prep! the prep is 95% of the job, it is everything!
Instead of trying to save money by doing stuff yourself, you would be far better off, doing a little overtime at work!!, doing something you know what to do!
Find a reccomended paint shop, get a firm quote, and expect to pay at least double!!
Tom