Upgrade question 2.0

Well, sorry beforehand but this is kind of a double post. I posted this same question in the GPU forum. However, the question relates to both CPU and GPU and thought I may get more responses if I posted here as well....



OK. Im looking to upgrade. current system is a little dated as far as OS and memory.

ASUS m3a78-em
ocz platinum 2GB ddr2 800
AMD 64 x2 5000+ brisbane 2.6 ghz
PNY 9800gt 512

I plan on upgrading my GPU in the future regardless, but would like prices to come down a little first. For now, Im looking at spending on the order of $150-170. In that price range I am considering one of two upgrades; either upping my CPU to a Phenom II x4 955 or getting a gtx 260. Looking at others' 3d mark scores for reference, it seems I would actually get more of a performance increase by upping the CPU and leaving the 9800gt in place for now over keeping the current CPU and getting a gtx260. Im assuming that while the x2 cpu i have now isnt hindering the 9800gt too much whereas it would be a huge bottleneck on the 260? I know 3d mark scores are somewhat iffy, they do provide a frame of reference. Average net increase with current cpu/gtx 260 ~300 points in 3dmark06. Net gain with phenom II X4/9800gt somewhere between ~3000-5000!...?

Thoughts?