I need Video Card that supports Pixel Shader 2.0

Okay hello everyone. Thanks for your time for visiting my thread. I really appreciate it.

I just downloaded a game called "Requiem : Alive", a pretty high-3d graphics game. After logging in, I only see nothing but black shadows in my monitor. I can barely see the people and buildings in the game. The Game said "Your Video Card Version doesn't support Pixel Shader 2.0. Game shutting down" :cry

As of now, I'm going nuts about what video card should i get that would support this requirements : (Game Requirement Source)

256 MB 3D graphics card with Hardware Transform and Lightning, Such as NVIDIA GeForce™ FX 6600 class card or Higher.
Direct 9.0c included or latest video drivers, and supports Pixel Shader 2.0 or Greater. Such as NVIDIA GeForce™ FX 6600 class card or Higher.

Here are my Basic Computer Specifications :

Operating System : Windows 7
System Manufacturer : HP
Model : p6241f
Processor : Pentium(R) Dual-Core CPU
Installed Memory(RAM) : 6.00GB
System Type : 64-bit

Currently Installed Video Card(Built-in) : Intel(R) G33/G31 Express Chipset Family

Obviously, my current video card doesn't support 3D gaming. I understand that this Chipset is only good for Video and Movie streaming and other 2d graphics.
I also understand the fact that i really need to buy a new Video Card that would support 3d Gaming and Pixel Shader 2.0

My problem is, I have no idea what video card should I buy. I dont want to buy a random card and stuck it inside my CPU, finding out later that it doesnt work. Nobody wants that.
So can you guys recommend the best and cheapest Video Card i could get that support these requirements? Please?

I also saw this Chart which would be very helpful : Click here