Low fps for a game called Aion online.

I got a probelm. when ever I'm playing this game my fps is around 6-15 and that's on good days. But when i'm doing massive pvping and massive wars my fps is 1-5 i can hardly do anything. so i was wondering if my computer is any good for gaming or should i upgrade it?

system:

windows xp home edition
verison 2002
service pack 3

computer info

Intel (R)
Pentium (R) 4 CPU 3.20GHZ
3.19 GHZ,
2.00GB of Ram.


Types

Processor: X86 family 15 model 6 stepping 5 genuineIntel ~3191 Mhz
Bios verison/date american magatrens Inc p1. 70, 05/01/2007
graphics card: Nvidia GeForce 8600 GT
Cuba cores: 32
core clock: 540 MHz
shader clock: 1.2MHz
memory: clock: 500 MHz (1000 MHz data rate)
memory: interface 128-bit
memory: 1024 MB
memory type: DDR2
bus: pci express X4

I hope thats enough info for someone to help me. if i still need to post any more info just tell me and if i need to upgrade my computer tell me on what things.
thanks.