The PSU you currently have could destroy your components if you attack the GTX 960 to it, cheap psu like this arent really meant for dedicated cards. I would say buy a new PSU for the long run, the EVGA 500B that jwcrellin suggested above is a good low cost option, but i recommend spending a bit more and get a higher quality components, that way your PSU will last till when you want to replace your CPU, Mobo and Ram.