Well, its your choice.
For example, my ex a few years back bought a new hp computer(sans monitor) for like $500 and then we put in a pretty decent video card for like another $125. Playing WoW she had capped frames and no game(computer) lag anywhere at any time. WoW takes more power than mabi and you could build something similar or better for less. I could of built her one for less but she wanted something sooner rather than later and the price was alright for what she got. (this was probably 4 years ago).
tl;dr, spend half as much nx for a few months and buy something better than what you're using :p