As long as your motherboard has a pci-e slot, you can use any gpu that will fit within the confines of your case provided you have the correct psu connectors. You also have the right idea in replacing the psu.
Yeah it has a PCIe Slot (x1) x 3 and a PCI3 Slot (x16) x 1
What happens to be the difference by the way?
And thanks for the reply.