I would try to find a machine shop to do it, I'm sure there are several around, unless you know someone that works with metal profesionally. however its never a bad time to learn, and with a bent frame, if you didn't try you'd be at a loss anyways, so of course its worth it to try to straighten it, all I can give you advise wise is to not hit the frame directly with a hammer, try bending it by hand or with leverage, and don't worry about cracking the paint, it'll happen!!

Good luck!