Can i have some advice on a PSU?

Hi guys i have got a atx 400 watt power supply all the info is below.
+3.3v +5v +12v -5v -12v 5VSB
28A 40A 17A 0.3A 0.8A 2A

People have told me that its not really that powerfull, i would like to get a new PSU but i would like some advice on what one to get, it needs to be a atx psu also is there a difference between a normall atx and a atx 2.0 PSU? im not sure. im looking to get one from www.overclockers.co.uk if someone could help me have a look on there for one id be really greatfull, i have been mainly looking at the antec psu's on there site

cheers guys

Liam

 

get either a seasonic s12-500 or s12-600...