Ok, so stick with the standard cooler for now, no problem,
Corsairs Cx500 is one I recommend quite a lot for lower end builds,
theres a psu calculator http://www.thermaltake.outervision.com/
put your intended build into it and see what it recommends but I think a 450/500W unit is going to cover you easily,http://www.tomshardware.co.uk/forum/284314-10-power-supply-guides-info
should be a good point of reference too, and once you find a psu you are considering, google 'ZXC500w psu reviews' and see what reviewers and owners say about that one,
if you don't know the one you currently have,
I would strongly recommend having a new one in the new build, how gutted would you be if the old psu killed your new chip and board?