Time to Upgrade?

Hey guys,

I made my computer about 3 years back. I don't know if I should upgrade though...

I usually play Warcraft 3 or World of Warcraft with friends, but I want to try other games now, and I'm not sure if my pc will be able to handle them.

CPU: AMD 3500+
RAM: OCZ 2x512 dual channel
Video Card: X800 XT
Motherboard: MSI K8T-Neo something or other, it has AGP slot only, no pcie
PSU: Ultra X-Connect 500W
Monitor: 17" Samsung syncmaster 710v (listed it cause I can get 1280x 1024 resolution, is that up to today's standards?)

I've been doing a little research on video cards, and I think the GeForce 8800 GT or GTS is in my price range... but since summer is coming up, and I'll be working a lot more, I would have the money to buy a new rig.

Thanks in advance...PS: I live in Toronto, Canada, so I don't know if I'll be able to buy new/top-of-the-line parts. I remember it took me a LONG time of searching to get my hands on the X800 XT (I think it's a PE lol, too long ago)