Upgrading an old system from 9600/9800 to Nvidia

Hi,

I have a few questions regarding upgrading an old system.

I currently have a

Antec Solo case with one extra fan mount on the front to cool the HDDs
Asus P4P800 with P4 2.6 (Northwood)
2G of PC3200 (DDR400) RAM
2 Seagate ATA 100 HDDs (one is main drive and one for page file)
a DVD burner
a Seasonic S12 - 330Watt PSU
and an ATI 9600XT (124 MB version)

I have a spare 9800Pro that also has 124MB but the fan is broken. My friend loaned me a Sapphire 800GTS and I noticed fairly well increase in game performance on CoH/CoV, Lineage 2 and WoW. However, if i am to get a Navidia 7600GT, would the CPU be a major bottleneck? Shoudl I get a new CPU and woudl that help (a 3.2G Prescott)

If so, would scale back down to 7600GS be enough?

I know ATI 1650 and 1950 (i know it would be an over kill and too expensive. my current budget is 100 dollars or below) draw more power so thats why I have decided to go the Nvidia route. If I go for teh 7600GS, there are couple cards on Newegg that have silent heat sink so it will be very quiet (not sure if i will need another fan though)

Thanks

The 7600GT can be found on newegg.com for under 100 and the 7900GS which would be even better can be found for anywhere from 100-120. If you can spare that, get it.

Specifically this:http://www.newegg.com/Product/Prod [...] 6814130056