New graphics card ~150$

Hi!

I would like to get some advice about buying a new graphics card and possibly more or new RAM. My computer looks like this;

AMD Athlon 7750 Dual Core at 2,7 GHz
2048 MB RAM DDR2
ATI RADEON 4600 Series 512 MB
Windows XP SP3

I wanna raise my FPS in games by upgrading. What would be a good choice of graphics card for me at about 150$. For getting more FPS, is it worth investing in more or completely new RAM and which one should I buy then?

I have a Silver Power 400W SP-400P2C.

Thanks for the quick response.

I am currently playing company of heroes and Left 4 Dead. But the important thing for me is not exactly what games I will play, but rather a more general performance boost.

Could you be as kind as to recommend me one or two specific cards?

The HD5750 might be an option, but as the specification table already says:
System Requirements Minimum 450 Watt Power Supply Requirement
Power Connector 6 Pin

If you're willing to take the chance...

I'm pretty sure the 9600GT is the best you can get at the moment, assuming that you have a HD4670. But like I mentioned before it won't give you a massive preformance improvement over the HD4670.

If you do go for it, try getting one with GDDR 3.

You might want to take a look at this page too http://www.antec.outervision.com/PSUEngine

Yep, confirmed that it will run on your psu, the HD5750. It's maximum power consumption is said to be 108 watt, should be possible on your rig.

Anyways good luck finding one, they're pretty rare here.