New card or?

Hello,i have a dillema and i want your experience to tell me your opinion,i make this computer before 2 years but it seems that for the new games is very old and i want to play games soo i must upgrade the graphic card or change it?to be honest is ok with some of the new games but low resolution and low-medium graphics.So because i dont have enough money to change it right now im thinking of buying a new graphic card like ASUS EN9800GTX+ DK/HTDI 512MB or 1GB PCI-E or (if you suggest sth else...) or a better one but i dont know if its ok with my PSU,i think will not be enough,tell me your opinion please,thank you
my computer specs are
CASE :THERMALTAKE VA7000BWA SHARK WINDOW BLACK
CPU :AMD ATHLON 64 X2 4200+ DUAL CORE
RAM :Kinhston Hyperx 2GB 2X DIMM DDR 1GB PC3200 (400MHZ)
MB :ASUS A8N32-SLI DELUXE
GF :ASUS EN7600GT/2DHT 256MB PCI-E 1.0 x16
:FLOPPY DISK DRIVE 3.5' 6.39 €
HDD1 :WESTERN DIGITAL 320GB WD3200JS 7200RPM SATA2
HDD2 :WESTERN DIGITAL 1TB WD1000FYPS RE2-GP SATA2('GREEN')
DVDROM :LG DVD 16X GDR-8164B BLACK
DVD RW:NEC DVD+/-R/RW ND-4571 LABELFLASH 16X BULK DOUBLE LAYER
KEYBOARD + MOUSE :LOGITECH DESKTOP MX 5000
SOUND CARD:CREATIVE SOUND BLASTER AUDIGY 4
SPEAKERS:CREATIVE INSPIRE T7900
WIRELESS CARD: ASUS WL-130N SUPER SPEED N WIRELESS PCI ADAPTER
TV :LG 22'' LCD M228WA tv pc compatible
and my psu
THERMALTAKE W0093 TR2 POWER 500W

yeah but to save a little money get a 9800GTX and overclock it to match the GTX+, easy way to save $30-50. i did check the sig in 2nd rig, those are GTX+ Superclocked speeds.

I only cited that because OP asked for power consumption of 9800gtx+, didn't imply it's a good deal.

But yeah, you can oc a g92 8800gts past 9800gtx+ too (like I do), and it would yield better results, since it does slightly more work per clock.
http://en.expreview.com/2008/04/03 [...] ew.html/12

As for x2 4200, it should still be enough for most games, as they're gpu bottlenecked.

you shouldnt have any issues, and good luck and enjoy!