Upgrading Computer for Diablo 3 NEED HELP

[MyBodyAsAShield]

OPERATING SYSTEM:
Windows 2.6.1.7601 (Service Pack 1)
CPU TYPE:
Intel® Core™2 Quad CPU Q8200 @ 2.33GHz
CPU SPEED:
2.35 GHz
SYSTEM MEMORY:
3 GB
VIDEO CARD MODEL:
NVIDIA GeForce 9800 GTX/9800 GTX
VIDEO CARD MEMORY:
1.79 GB
VIDEO CARD DRIVER:
nvd3dum.dll
DESKTOP RESOLUTION:
1280x1024
HARD DISK SIZE:
596.16 GB
HARD DISK FREE SPACE:
545.32 GB (91%)
DOWNLOAD SPEED:
1.02 MB/s (8.5 mbps)

And I have a nforce 750i SLI Motherboard with a 700 watt power supply.

I know I want to upgrade to a 560 Ti video card but I dont know what else should be on my priorities to upgrade, any help would be appreciated

 

[vigilante212]

It would be easier if we knew how much you are willing to spend. And what version of windows 32 bit or 64 bit

 

[MyBodyAsAShield]

windows 32 bit, and around 700 or less