You can't upgrade those AIO types because they have no expansion slots for a graphics card.
Those kinds of computers are only meant for people who don't game at all, or do very little gaming. It will play games like Warcraft III just fine but nothing like Battlefield 3 well or anything like that.
If you wanted a computer to do gaming for future use, as in you, maybe wanting to play something a little more graphic intensive you should have thought about getting a computer with room for upgrades such as a computer tower.
Course towers take up space and compared to an AIO solution, probably not an option you wanted to begin with.
Can't help you out any more than that
😞