Upgrading Video Card on Mac?

I have a mac that I downloaded TF2 on, which has a minimum requirement of a NVIDIA GeForce 8 or ATI X1600. I bought my mac a few years ago, so it has an Intel GMA X3100. Is there a way to upgrade the card itself to increase its abilities, or do I have to buy another card? If the latter, what would be a capable card for a college student with minimum wages? Thanks.|||There's no way to upgrade the graphics card on any laptop, Mac or Windows. First of all, you have an integrated graphics card. It's not actually a separate chip, it's a part of the motherboard. Second, if you were to try to upgrade the card, you'd have to pull the whole computer apart.