if so you may be able to get a 9800 256mb card it is the fastest mobile card around - you would need to check compaq site however to see if the system could handle the card
If your laptop was the 'mid-range' version of it's model, it is possible you could buy a motherboard for the 'high-end' version, which might have an upgraded video card. However, this is tricky, most of the time if it even exists, it will be hard to find, and when it comes down to it, it would probably be more cost-effective to sell your laptop and buy a new one with the money you saved from not buying the upgraded mobo.