You're gonna want something other than that old power supply to feed power to those delicate components. You'll want at least a 500-600 watt PSU. It's also a good idea to make sure that the PSU is 80+ certified.
As for the GPU, adobe programs like cuda cores. This is something only nvidia cards have. The GTX 670
would be ideal. However, considering this won't fit in your budget, you're gonna want to grab either the GeForce GTX 570
or the SAPPHIRE Radeon HD 7870