Power supply

[koopdaville0]

Hello,
I need to know the best psu I can get that would fit in a SX2802 model Gateway slim desktop!

 

[C12Friedman]

At least out of those available from newegg, I would say the FSP FSP300-60LG 300W
http://www.newegg.com/Product/Product.aspx?Item=N82E16817104145
which measures 5.91" x 3.21" x 1.6". It is also the most expensive from them.
Don't limit yourself to Newegg, basically what you are looking for is a "mini ITX PSU" but do check the measurements just to be sure what you select will fit.