You should have the ATI control manager installed (If you're running Vista, right-click on the desktop and it should be one of the menu options). If not, download the driver from the ATI site (linked above) and install it, as it will most definitely have the ATI control manager, which is where you can change anti-aliasing settings.
Well for what it's worth it appears ATI do not support their laptop cards. I used Mobility Modder and the standard desktop HD 2400 drivers and it appears to work fine.