Since i wasnt that much budget constrained i used this case, notice that it has an integrated power supply that use a DC adapter like a pico PSU but contrary to the latter it use a 19V DC adaptator so the ATX 12V has yet another converter to go through while a pico PSU use a 12V DC adaptator that reduce the requirements of the ATX DC converters.
Since the MB has a DC input i didnt use the case PSU as the former has better efficency overall but the case is good to be upgraded as with thoses commodity PCs you change the MB + APU in 5 years for 80$, ther s no need to really look for future ugradability, changing thoses two elements will be the cheaper and by far the most efficient way.
Temperature delta between room and the inner casing air was 12°C when the plateform was absorbing 25W, you ll notice that the 5350 fan will be at about 2cm of the holed plate, this allow to pull a really tiny amount of cool air, the panel on the top is not very big and do not allow for a large convection.
Edit : Why are you stuck on the 1.3 Sempron, what is it about at 1.6 and 2.05 since you have the good chip.?.