bottlenecked by agp slot

[Sooraj_digit]

I have a Pentium 4(2.93 GHz) over clocked to 3.41 GHz(155 *22), 512 DDR (400 MHz) ram, 80 GB HDD and a MSI 915GLM-V motherboard with AGP 8x. I want to buy a graphics card which would be able to run the new titles. I am not a hard-core gamer and I can bear lower resolutions of 800*600 at 25 fps. Please suggest me a graphics card capable of running the new titles (2007 onwards) or suggest me a motherboard with nVidia based chipset. I have a small budget of 5K ± 1K and is my over clocking safe at max. temp up to 48°C.

[nvidia]

^^If you get a new motherboard, then you'll end up changing your processor and RAM too..
You can get the 7300 for 3-3.5k.. I think the 7600 AGP costs about 4-4.5k..