First off, welcome to the forums!
It would be very worth overclocking that card! I have a freind with one, and they tend to overclock quite nicley! I don't remeber exact clocks, but it was enough to get him playing BF2 with little lag. The best ways to overclock are either with Coolbits 2.0 (get it from www.guru3d.com
) or ATI Tool (get it from www.techpowerup.com
. Don't worry, it does Nvidia cards, too.)
You should also look into some modded drivers, like the NGO or XTreme-G. They boost performance a lot, and often improve quality, as well. I personaly am very fond of the Xtreme-G 96.89's, they are a great driver set.