You might not need a new video card...try this first.
from the desktop click START, right-click MY COMPUTER>properties>hardware tab>device manager
Next to where it says "display adapters" click on the "+" sign. On the submenu, right click and then click "update" and see if Windows will look on the Internet for an updated driver...
If that doesn't fix the problem then most likely you need a video card that support the higher resolution
edit: I'm not sure if you can get to Device Manager that way in Win2000. If you have a hard time finding it, just type:
devmgmt.msc into the RUN command