Although I don't know much about your graphics card, I do know that the rest of your computer will have no problem running CoD4.
I have a Geforce 9400GT and it runs fine at minimum settings.
If you would like to make sure you can run it, here's the demo.
Just a warning, it may be a bit buggy due to not having any patches.

i played the demo, and it runs very well actually. the only issue i see is the graphics get kinda laggy/buggy with everything going on on the screen, which is kinda hard to avoid
other than that, the game runs smooth, so i may pick it up for christmas. i assume eGO will still have servers, because that's the main reason i want the game.