every 10-20 mins it just shuts off......when i feel the power supply it is feels hot as hell.  do i have to get a new power supply or would i have to send it in to repair?

See if you can borrow a PSU and try it.

DO NOT:
http://www.theregister.co.uk/2007/08/24/xbox_teen/

Haha what an idiot!!

If it was a console overheating issue you would usually get it shutdown with 2 flashing red lights on the console.  If the PSU is hot and in particular the light is red then get another psu asap before you damage the 360 itself.

do they sell psu's in stores? or would i need to contact microsoft?

Trying a new power supply would be the first troubleshooting step I would take. 

I googled "xbox 360 power supply" and got some results. Keep in mind that different iterations of the 360 have different power supply bricks. You'll have to figure out if you have a Jasper or one of the other versions. If you do end up buying one online, I'd suggest getting it from a place like Amazon so that if you have to return it there should be no issue.

The "metal" ended 203W PSU's will fit all the old style 360's and you can usually pick them up from ebay.  Failing that a local computer shop might have replacements in stock from older consoles they've perhaps scrapped.

Try a friends if you have one with a 360 would by my first bet.