I have a Dell Optiplex GX280 tower that I added a Evga 9400GT PCI-E video card to. The system boots Windows 7 and ran fine for several hours with no issues. On the system requirements for the video card it said I need a 300watt PSU capable of giving 18amps to the 12volt PCI-E bus. The Dell PSU in the system is a 250watt that provides 1amp to 12volt but doesn't say what. The system will be used mainly for internet and word processing with some light 3d gaming with older games.

Should I be concerned? I'm worried I will not be able to find a upgraded PSU for this Dell unit that with work with the motherboard.