Nes Clone gamepad to usb

[Kame]

First of all hi everyone! I'm new to this forum, I've done a few case mods and soft mods but I never done any hardware mods before. So to start off I want to make my Terminator gamepad to work for the pc. I currently have no idea to what to do, but I'll post the picture of the circuit board. I know that I'll need a micro controller but which one?