Vista - Best NVIDIA card for my DELL GX270

Hey Guys!
I recently purchased a REFURBISHED DELL GX270 which has 3 GHZ processor and 1 GB of RAM from local market here in PAKISTAN.It came pre-installed with WIN-XP but I want to upgrade to WINDOWS VISTA and want to add some 3d card which will enable WINDOWS-AERO graphics on desktop.
You can view my computer specs at Documentation
Can u please some NVIDIA GEFORCE card which will atleast enable windows aero.
I think I should go for

GeForce AGP FX5500 256MB (128-BITS)

GeForce AGP FX5500 128MB (128-BITS)

GeForce AGP FX5200 128MB (64-BITS)

CAN U PLEASE TELL ME WHAT CARD should I purchase and that what is AGP or PCI.

By reading my pc specs, can u tell me its AGP or PCI compliant but I think its AGP compliant.

I SHALL BE THANKFUL FOR ANY HELP U MAY OFFER.

Well, if your model is the desktop model, then yes. if it's the small mini computer sytle. then you''ll have a hard time getting something to fit.. Maybe look at something like this. I know the best card you could get would probably be the AGP Sapphire 3850.. it can run Crysis, no other AGP card can as good as it. not sure if that matters, but it's probs one of the best cards thats not a PCI-E card.

Look here.
Newegg.com - AGP 4X/8X, Desktop Graphics / Video Cards, Video Cards & Video Devices, Computer Hardware

I had an ATI x1650 Pro 512 MB card that worked really really well with Vista, and played games like NFS:MW Black Edition with no issue.

Processor was a P4 3.2 GHz HT Prescott, and I had 1 GB of RAM, that I later upgraded to 3 GB.

please make sure that GPU you recommend works on my PC.(C SPECS)

I think my idea works.. AGP 4/8 correct?

Yap I hope so dude but I am concerned by some one,s comment on nvidia forum that I should also buy DELL POWER SUPPLY which might not be available in local market.
Let me talk to my computer hardware store.

that rig is very old....... vista will struggle

but this will run Aero....as johngalt said its not a bad card
ATi Radeon X1650 AGP 512MB DVI Graphics Video Card on eBay, also Graphics Video Cards, Graphics, Video TV Cards, Desktop PC Components, Computing (end time 18-Aug-08 14:25:06 BST)

this card also requires no external power source
& is far better than the 3 you listed

Ummm, actually, *mine* *did* require an external power source....

Welcome to Visiontek: Unbelievably Real Graphics

System requirements: 350W PSU....

I burned up my 250W testing it (just had to try) and then bought an XPower 500 that bit the dust so I then got a MadDog Multimedia 500W Modular PSU that I still have in the case with the card. Works perfectly (albeit a bit slowly) on Vista.

System Requirements: PC with one 8X/4X AGP graphics slot available on the motherboard. 350-Watt power supply or greater (assumes fully loaded system). 512MB of system memory. Installation software requires CD-ROM drive. DVD playback requires DVD drive and decoder software (not included).

yes it does require a 350w min but my point was it only requires that through the PCI bus ....there is no PSU connection on this card

How much did you want to spend?