So, i just bought terraria only to find out i dont have a 9.0 shader graphics card (even though it says it is, its not). I currently have a reordon(Is that how its spelt?) 9700. Ive also had it for.......12 years now. I need a cheap but good card. Any ideas?

Sup, brosive.
What is your budget in buying your new video card?
If you're looking for something cheap and decent for gaming, get an
Nvidia Geforce GT 440 for only around 70 dollars.

would not go past $100. Also i have Windows Xp pro. If that matters. Witch im guessing it does not.

Read the readme for the computing subforum, there is a dirty great big image that will list out all computer components for any budget, the GPU that you want will be on there probably, just make sure the socket is compatible. If you don't know what socket you have google and find out.

I'd also recommend a processor/mobo change, I've also had a radeon 9600XT for a long time with a pentium 4 processor, well.. a graphics card upgrade only wouldn't have helped much.

More or likely if i have to get a new processor im going to look into a whole new pc.

Getting a new PC would be a little more expensive than building one considering there are overpriced PC(s) there.

For your video card, I would suggest an Nvidia GT 440. (this won't go above 100 dollars)
If you wants to get an ATi, then go for the ATi Radeon HD 5770.

For the CPU, an i5 2500k will be good for gaming, or even Video Editing.
^_^

A 12 year old motherboard is in no way guaranteed or even should be able to use a GT 440 or an i5. A 9700 is not the same slot-type as any modern graphics card is, so a motherboard change is necessary.

Buying an entirely new computer is definitely the physically easier option, but buying a specific graphics card to add to the new computer is almost certainly necessary for a decent gaming platform as well.