Vista - Need help with pc gaming

Hello all, I just bought me a new pc ( HP Pavilion dv9925nr Notebook PC) and to go with the new pc, I bought Call of Duty 4. Just trying to play the Single player game resluts in very slow game play and unsmooth playing experience. I am pretty sure that I have updated my drivers which caused the game to become playable with everything off and at a low resolution. I am not sure on what specs I need to include but here is what have.

Model: AMD turion 64 X2 Mobile Technology TL-60 2.00 Ghz

Memory (RAM) 4.00 GB

System type: 64-bit Operating System

Nivida Geforce Go 7150M

CoD 4 is going to put a heavy demand on your graphics chip, which wasn't really designed for heavy gaming in the first place. However, since it's such a great game, it would be a shame if you weren't able to enjoy it.

I would get the latest DirectX update: Latest DirectX Update.

After that, right click on the desktop, select NVIDI control panel. Under the Adjust Image Settings with Preview menu, use the slider at the bottom to run your drivers on "performance" instead of "quality", which is their default.

A lot of bad play may also be coming from your sound settings. I'd turn sound details to low and to off wherever given the option.

If it's still not quite there you can further adjust your 3D settings by going back to the nvidia control panel and using the drop down menu under program control to adjust call of duty iw3sp.exe

Ok so are you saying that my Graphics card is not sutible for the game that I want to play?

If so do you have any suggestions on what I should be trying to get???
also I son't want to spend a lot of money but at the same time I don't want anything cheap.