Need to upgrade video card in my Asus CM5570 system. Suggestions please?

My system is:



OS:Windows Vista 64 bit Home premium

Brand: Asus

Model: CM5570

Processor: Pentium(R) Duel core CPU E5300 @ 2.60ghz 2.60ghz

Memory: 6gb DDR2



I want to play Bioshock and other games, but saddened that it is below the system requirements. =\

I would like to be able to get a new video card and whatever else to make my system more efficient but have no clue where to start.



Suggestions please?

Thank you for all the help/.|||Well, that particular Asus comes with a 300 watt power supply, which limits your upgrade options.



The best cards you could install without having to buy a new power supply are:



GeForce GT240

http://www.newegg.com/Product/Product.as…



Radeon HD 5570

http://www.newegg.com/Product/Product.as…



Either would be fine for casual gaming, but for more demanding titles you'd want a graphics card closer to $120 like the Radeon 5750 or GeForce GTS 450.

http://www.newegg.com/Product/Product.as…

http://www.newegg.com/Product/Product.as…



However, since those cards require more power, your total upgrade cost would be closer to $160.

http://www.newegg.com/Product/Product.as…



Performance:

http://www.techspot.com/review/240-ati-r…