Finding the right video card for my computer?

My family recently got a new computer which is relatively high end on everything except the graphics card. It actually has trouble getting things as simple as the Orange Box or even Minecraft to work.



What are some good choices for video cards that can handle games well for under $150? I want to be able to play Portal 2 when it comes out with out lag :P



PCI express by the way|||You could either get:



Radeon 5750 ($119.9 on Newegg)

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



Radeon 5770 ($129 on Newegg)

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



Or GTS 450 ($114)

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



The reason I suggested these cards which are below $130 is because you also need to spend extra on a new power supply unit.

Your OEM power supply will likely not have enough wattage to support these cards. They need 400-450 watts minimum.



Something like this should get the job done: Antec Basiq 430 watt PSU:

http://www.newegg.com/Product/Product.as…|||NewEgg FTW