Bad purchase but how to fix?

I just bought my first bike from craigslist for $1300. Far more wrong with it than the dude said. It's a 1983 Suzuki Tempter GR650 ("D" I think). The front wheel isn't aligned with the handles and the tires are old and cracked but hold air. No keys; I can turn it on with a popsicle. My main problem now showed when I tried to change the oil. The oil plug was held on with a brownish epoxy and the metal threads I see are practically gone. I cant find the part anywhere and dont know if it can be repaired. My dad says just to epoxy the hole shut and remove the pan for every oil change.[color=#333333]Nox[/color] [color=#333333]VidMate[/color] [color=#333333]Mobdro[/color]