Upgrading an HP a1540n computer

I want to upgrade this computer to enable it to play The Sims 3 and would love a little feedback regarding the video card...

Basically, specs are

AMD Athlon 64 X2 Dual Core 4200+

2.2 Ghz

2G PC2-4200

NVIDIA GeForce 6150 LE Graphics

300W PSU

Planning to beef up PSU with 430W Thermaltake...

Video Card: game requires min 256MB -- looking at NewEgg, I've found:

- Gigabyte GeForce GV-NX72G512E2 7200 GS 256 MG $24.99

- EVGA GeForce 256-P2-N429-LR 7200 GS 256 MB $25.99

- EVGA GeForce 256-P2-N436-LX 7300 GS 256 MB $32.99

- EVGA GeForce 256-P2-N761-TR 8600 GTS 256 MB (GDDR3) $29.99 after rebate, which expires 6/30

With an older computer, I'm not wanting to get too crazy with the upgrades so would probably be happy with either 7200. With that price on the 8600, though, I would like to know if the computer could handle it or if I should leave it alone!

Thanks to everyone responding - much appreciated!

Thanks. I'd already checked that out so all 4 are PCIe x16. Any suggestions as to which of the 4 I should buy? 3 are GDDR2 and the 4th is GDDR3, but at a good price.

I built a new computer last year and familiarized myself with components then. This info is for my sister and, with it being an older computer, I want to make sure the parts are compatible, something I didn't need to worry much with on mine! Would love to hear from someone as to what their preference would be when doing the video upgrade. Who knows, someone may even have better suggestions!

Thanks in advance for your help with this....MUCH appreciated!

BTW: MOBO: Asus A8M2N-LA

Skip the 7200/7300 becasue it's geared more towards video rather than realtime graphics.

Go with the 8600 if it's the best you can get because its a gaming card (although not a very fast one).

Thanks for responding. That's what I told my sister to do so grateful for the confirmation!