well the sarcastic answer is.. sure it can.. all you need is an adapter.. the adapter consists of just one hammer and maybe some glue.. First step.. pound it in tight.. and then use some glue if needed.
OR like a real answer would be if you want to upgrade I would save some money and get a new motherboard, CPU, and Ram and other stuff if needed.
you didn't say what you have currently for the GPU.. as depending on what you have for current CPU, Ram, GPU etc.. it may be that your GPU is not being bottle-necked by your CPU as we don't know what you have.