Is this inside a Packard Bell chassis?
jip, it it. Looks something like this:
Damnit, that doesn't make it easy. If you want to stick to that chassis, you'll need a single-slot GPU. If you move to a new chassis, PSU and GPU that would be better.
GIGABYTE GeForce GTX 750 Ti 2GB GDDR5 @ R2220 (GTX660-like performance for a grand less once overclocked)
Corsair VS350 350W @ R443
Cooler Master Elite 344 @ R433
Total: R3096
May I recommend the Asus non Ti?
It is slim enough to fit into the case.