DO NOT trust the PSU that comes with that case. Virtually anything from Seasonic, EVGA, XFX, Antec and Corsair will be better. If you plan to overclock get a 500w model. If you plan to overclock AND get a more powerful GPU in the future, get a 600-650w model.
The PSU that comes with your case at best will not supply its rated power and will not last long particularly if it gets warm. At worst it could be a fire hazard or ruin some of your other parts when it breaks.