Not too sure buddy but first you need to make the bike look good. Not the speed at the moment.
Get some new plastics and/or sticker kit and give it a good old scrub. Get an old toothbrush and scrub between everywhere!
New exhaust and just basically buy some parts. Maybe handlebars and a new kill switch & new billet fuel cap, exhaust, grips, levers, air filter and pegs. Also, buy a new NGK spark-plug.
That's what I would do. Haha.