need advice for computer upgrade

Hello all, Im looking to upgrade my computer mainly for FPS and Graphics for armed assault game. My specs now are: AMD Athlon 64 fx 2.61g
Nvidia 7900gtx 256m
Asus A8N sli deluxe
19 inch samsung monitor
2 gig ram
650 watt power supply
3 cooling fans

I want to upgrade to the Nvidia 8800gtx 756 card and maybe a 1000watt ps and also the Nvidia nForce 680i SLI. Would i get a real boost in graphics and FPS with this setup, or should I wait a while till new items come out. Would i get a real boost simply by getting a Nvidia 8800gtx 756 card, would i need more power than a 650watt supply. Money is not a problem, i want to get the fastest and best graphics all on high settings money can buy, what are your opinions please, thanks all.