600W should be more than enough.
You can find your specs like processor, Ram e.d. when you right click on the picto "computer" or " my computer" at your desktop. Then click on the last one on the bottom, it's called "eigenschappen" in Dutch, don't know in English, maybe "settings" ?
You can also download GPUID-Z and GPU-Z these tell you everything from your system. ( except psu i believe )