COD2 is pretty demanding, and it's mostly about the video card and it's settings. My desktop is having some trouble in some scenes.
Look for a website that has tuning suggestions for the game. I know smoke and shadows used to really slow down Nvidia frame rates, so if you can turn those down, it might allow some of the other settings to be higher.
What resolution are you playing at? If you lower the resolution you'll probably see a lot of improvement in frame rates, though you'll lose a little detail in the graphics.