a 600w power supply usually is really a bad 250 watts power supply
it is not rare to see them just burn themselves and sometimes kill the mainboard with them, cpu also
you shouldn't save money on some parts, there are critical and non critical parts, this one is the most critical
if you don't apply much load, then keep it until you can buy a real psu, 450watts minimum, depends on the gpu and if you plan to add another cpu that could possibly be oeverclocked
the base of most people is a evga 450watts psu, or a corsair in the same range