Lol, a 9800 pro is still a damn good card. HL2 is more demanding than this game. If anything your CPU is bottlenecking the card (no big deal here thoguh).
Lifire is correct. It's more likely that the CPU will be the bottleneck than the video card. In fact, the video card should run the game easily on high settings.
Pfft, Halflife 2....demanding?!? Hell, it runs Doom3 golden! (Gets a wee bit hot though... ) I've never had to turn a setting down in GW with my 9800Pro.