Sogi-Ya: http://code.google.com/p/x360ce/
sort of redundant because it seems like it's covered by MotionJoy, but this is for the standalone xInput emulator (AKA Xbox 360 controller pc emulator: thus "x360ce")
what it does is emulate DirectInput controller commands into xInput; it's not going to solve your PS3 controller driver problems, but once you do find a driver for it you can use this program to emulate any controller using DirectInput into a xInput one (driving wheels, joysticks, gamepads ... pretty much anything).
as I said: apparently it's kinda redundant in light of that MotionJoy thing because seems to cover it as well as provide the driver for the controller, but MotionJoy lists it as a beta feature and could cause BSODs ... so maybe it would be better to trust in a proven program.
... I'm guessing that 360 emulation support is your main issue, it's the only thing that gets pissy about what kind of controller your useing.
I've never experienced anything like a BSOD using MotioninJoy (to the point where I don't even think I could if I tried). That driver looks interesting though... I'm already comfortable enough with my program to not want to use that right now, but @OP if you have trouble with MotioninJoy then try this.