Goes without saying- trash the intex psu. If you are going to be stuck with onboard, you can go for VIP silver 500w or cm 390w. But if you are planning to put a graphic card in the near future- it depends on what kind of graphic you will plan to buy.
The competition for 9300 nvidia chipset is amd 790gx to be honest. Check out the conclusions yourself:
http://techreport.com/articles.x/15690/13
You can go for it, but as you see it on the conclusions- eventually you will have to get newer drivers and update bios. In this day of age, BIOS update and drivers is inevitable if one wants optimal yield and if one wants to get the machine working properly on any current systems.