No need to overclock it or anything to be honest, the 555 isnt a bad GPU at all for the price of the laptop, can quite comfortably manage BF3 for me at the minute on pretty high settings, infact I've not had a problem with any game including Witcher 2 which only problem it did have with my laptop was optimus was kicking it over to the IGP for some odd reason.(Which is easily solved in a couple of button presses).
Thats one thing to look out for if you think a game is running pants make sure optimus is behaving and it hasnt kicked over to the IGP.
Thats one thing to look out for if you think a game is running pants make sure optimus is behaving and it hasnt kicked over to the IGP.