X1650 Pro (agp) vs 7900 gs oc (pciex16)

Hi, I bought a new motherboard recently, and it supports agp and pciex (It's the asrock dualcore sata2 one)
and I was wondering something about an upgrade possibility. I have the opportunity to purchase a new 7900 gs oc for only $60, and I'm curious to know if it would be a noticeable upgrade. I currently play cod4 and counterstrike, and I've tried ut3 previously. I play on a 19" monitor @ 1440x900 native resolution.
These are my system specs

Proc - E2160 1.8ghz (oc'd stable @ 2.66)
PSU - 450W
RAM - 2gigs DDR2 667
GPU - X1650 Pro 512mb DDR3
CPU cooler - COOLER MASTER RR-CCH-L9U1-GP 92mm Hyper TX2 CPU Cooler
Fans - 1x120mm 2x 80mm
Case - Xblade Midtower

I haven't tried cod4 with my new system yet, since I have to reinstall it because of the reformat (ugh) so I don't know how much of a performance boost I'll get from that. I usually though, will all settings off, get around 50-70 fps on max res. I'd love to be able to turn on some eye candy, since I go to lan's and people are pretty much rated on their rigs. Thanks for your help, and anything will help, suggestions, possible alternatives, $60 is pretty much all I have to work with though.

Yes its a noticable improvement. here is toms own chart to compare the two http://www.tomshardware.co.uk/Gami [...] 9-8.html#.
Mactronix

How about this, I found a deal at newegg with a new evga 8800gts 320 for $110 after mail in rebate, would that be a good idea, save up for that? I've seen plenty on that, and was already looking into it.

okay, which leads to another question. Both the 8800gs and the 8800gts (320) are around the same price range, I'm interested in which one is better, power-hunger wise and heat, and of course, power. I'm looking to try to play cod4 with most things on, AA and AF aren't extremely important. Depth of field and specular map would be awesome, but on my current system the fps drops to around 20-30 with those on. I'd love some more opinions, thanks again