QUOTE THE CHIMP:
KEYBOARD AND MOUSE, FOOL
edit: I have the exact same one as you. Set your gamepad config right. You will never have the same accuracy for the simple reason that most controllers are force sensitive to the amount of pressure you put down on the button and the ones for computer arn't, not to my knowlege, and not for under 35 bucks. I could be wrong though. (its been known to happen)