HP P6216F video Card choice

I am totally new to OSX on PC but Im learning little by little, I was able to Install Snow Leopard 10.6.2 on HP P6216F, I already updated to 10.6.3. these are the specs

Motherboard M2N78-LA (violet)
Cpu: AMD Semprom X4 9150e
Sound Card: Integrated: ALC 888s (Working with ALC 1200 kext).
Ethernet: Both working (ehternet and wireless) without any patches.
Video Card: Integrated Nvidia 9100 (NVinject)
Memory: 8gb ddr2

Whats Working:
Snow detects 1 processor 4 cores
Sound Card gets audio but just digital output trough RCA .
Ethernet: Lan Works 100% haven't tried much the wireless.
Memory: Have to bot with maxmem=3839 or else it shuts down.
USB: used usb fix but my keyboard and mouse sometimes lost power (I am using PS2 patch to use ps2 keyboard and mouse it seems to work fine)
Firewire:Haven't tried that.

Not Working:
Card Reader: It doesn't detect any card.
Video: This PC has and integrated Graphics Procesor Nvidia 9100 I was able to change resolution via command line on start up: Snow detects
Type: GPU
Bus: PCI
VRAM (Total): 32MB
Vendor: NVIDIA (0x10de)
Device ID: 0x0847
Revision ID: 0x00a2
Display:
Resolution: 1024X768
Pixel Depth: 32-Bit Color (ARGB8888)
Main Display: Yes
Mirror: Off
Online: Yes

Though my research, I was a little bit confused about this integrated card, because I see some netbooks with integrated intel Video, can get hardware acceleration. Seems like IGP its not yet supported with nvidia.

So I decided to go for a new Video Card. On my country I have to choose between
Nvidia XFX GT240 512 DDR3 or XFX GeForce 9800GT 512ddr3. So witch one should be better to invest for my PC, I want to run games in windows too

Thank for helping me!