I have a question regarding upgrading my GPU for my PC.These are my current specs.
CPU: AMD Phenom II 820 Quad-core
GPU: NVIDIA GeForce 9100
RAM: 8GB DDR3
PSU: 300 Watt I don't know the manufacturer, sadly
Resolution: 1600x900
I want to upgrade my GPU to the Raedon HD7770 I also know that I need to upgrade the PSU. My budget is about $200.
One last thing that I need to know, do I need to replace anything else to run the GPU?
Thanks, and any help is appreciated

EDIT: The games that I want to play are mainly Skyrim, Guild Wars 2, and some other Indies.
