Wow, I can't believe you actually went out and bought a new GPU for a game you're not even sure you want to play? Anywho, the 470 shouldn't require any overclocking to handle this game. Just leave it stock and be happy. To be honest, you won't get an amazing performance boost from overclocking the 470 to begin with, maybe a couple FPS at most with this game, and considering the 470s run hot to begin with, I wouldn't recommend it for a novice overclocker. You run the risk of damaging your graphics card.
Now aside from all that, if you're still serious about looking into overclocking, your best bet is to go read up on a PC hardware forum, like Tom's Hardware Forum, and get some quality info.
Edited, Sep 18th 2010 6:21am by zeruin