I agree. I would consider swapping it out for one from Seasonic, Corsair, Antec, Enermax, XFX, PC Power and Cooling, etc. I think BeQuiet! is a good brand in Europe too.
One of the reasons I was suspicious is that quality power supplies almost never come with cases. When they bundle its usually because its a crappy unit that cant stand on its own.
As long as you are running a quality PSU, I would say you should find something between 450w and 600w with more than 85% efficiency (the higher the better).