MIn PSU for my epia M1000 mobo

hi
need some help here
Now got one off the via epia m1000 mobo wich is very nice :D but as i was looking for all most 0 noice i have not to modd is brought some small itx case with had a 150 W PSU
But have put the box into my workdesk its now getting a bit warm:eek: 65 C load so i can see the heat is coming from Hdd and PSU so i was looking at one off the ext psu thing but how big will it have to be
thing is this box
sony DVD-writer
120Gb WD SE
512 Mb Ram
Floppy Drive
A graphics Card POssible a fx5200 or just a ati9000? don't know yet
mobo off curse!!!
plus is it possible to put something else on as a heatzink with dif fan ?
have any off you out there done this ?
any help please