I have a prebuilt (Gateway FX6840) from about 2 years ago, and I wanted to upgrade the graphics card, but I'm a little worried about the rest of my computer keeping up though, namely with the possibility of my CPU bottlenecking and my PSU blowing up. I'm mainly interested in turning up the graphics a bit in games like Skyrim, Witcher 2, and Dark Souls. I generally run things at 1920x1080.
CPU: Intel i7-860 at 2.8GHz
GPU: Radeon HD 5570
PSU: FSP 450-60EP (500W peak, 18.0A on each 12V rail for 360W total)
RAM: 8GB DDR3 1333MHz
Chipset: Intel H57 Express