If both the X1300 and Radeon 9550 don't work on your system, chances are that you have only PCI slots on your motherboard, seeing that you have a Radeon 9200SE. If you want to increase gaming performance, the best thing you could do is to save up around 600-700$ then you can get yourself a pretty decent pc. Just make sure you don't upgrade your current pc, because you won't make a big difference ( even the latest PCI card is considered non-gamer friendly) . It's also a waste of money, now you can just play on lower settings and wait till you have enough money. I know the pain man, my primary gaming card is a 9550. I have to play even warcraft 3 on 1024x768.
Good luck and enjoy your stay in TF.
Intel Core 2 Duo E6420 Conroe 2.13ghz
Gigabyte P35-S3 Motherboard
A-DATA 2x1GB DDR2 800mhz memory
Geforce 8600GT 256MB GDDR3 PCI-Express