Solved: Upgrading from 256MB Radeon ATI HD 2600 XT?

Okay, I'm buying a computer from dell with a 256MB Radeon ATI HD 2600 XT. It doesn't say anything else about the card. It doesn't say the motherboard.

Heres a diamond viper brand of the card:
http://www.newegg.com/Product/Product.aspx?Item=N82E16814103037

The question is, could I throw a EVGA Geforce 8800GT into my computer?
http://www.newegg.com/Product/Product.aspx?Item=N82E16814130318

The PCI on the Radeon is PCI express x16.
The PCI on the Geforce is PCI Express 2.0 x16

128bit on the Radeon
256bit on the Geforce.

So, could I yank the crappy radeon and replace it with the geforce? If not, whats the best card under 175 USD that I could buy? I'm a gamer.

Thanks
- Caesis.

 

Go for the Radeon 4850 instead of GF 8800, it's better: http://www.newegg.com/Product/Product.aspx?Item=N82E16814121253 or a cheaper version: http://www.newegg.com/Product/Product.aspx?Item=N82E16814102770
Whatever graphics card you will get, you will need a new, more powerful power supply, that's another 50-70 $ at least, and your Dell's case hasn't got well enough cooling, so that's another thing to consider...

Rather build you own than upgrade a Dell. period.