The main problem is that the R5 330 consumes 50W and the GTX 960 consumes 130W.
As it is 80W more, your PSU must have a sufficient margin. It should be about 400 watts of good quality (80+). Also, as the consumption of the GTX 960 exceeds 75W, it needs the PSU to have a PCIE connector (surely with 6 pins).
Additionally you must measure the space available in your case and choose a GTX 960 of smaller dimensions to fit properly.