Thinking about upgrading to a 7600 gt agp, need advice

Okay, So i have a 4ish year old Dell Dimension 8300. It has a 2.8 ghz Pentium 4 processor, and 1 GB of DDR Ram, 2 256mb modules and 1 512 module. It also has a 9800 Radeon Pro 128mb AGP Card. My computer has been fine for playing most games but on some newer titles i've been playing like Medieval 2 total war and Rise And Fall, My Computer is starting to show it's age.
So I was thinking about getting a 7600 GT AGP to replace the 9800. I just sorta wanted to know how my computer with a 7600 GT would peform compared to a brand new computer with say, a e6300 and 1gb of DDR2 with a 7600 GT? Also would my computer be able to play most games coming out in the next 2 years

cool, thanks, just one more thing. If i get a 7600GT, would i get a bottleneck with the CPU when playing newer games?

Good luck finding one in AGP!