Its possible, however we need to know a lot more about your computer, and possibly your needs. I take it you game since your not happy with the performance so what kind of games do you play, what quality do you want out of them and what is your resolution.
Next we need to know your motherboard, CPU, ram, and PSU. For the first three you can find these out using a program called CPU-z, for the last one if you dont know you will have ot open your case and write down what it says on the PSU sticker.
Lastly, what is your budget.