Im concidering buying a used PS3 and need help?

its a 80 gb and i think its the phat modle but i need to know how mutch longer the ps3 is going to be in use (like before something new comes out) and i need to know if $115 fo it is a good idea it comes with the game of the year Oblivion, i also need to know if they are still comming out with updates for the phat ones, and can i do anny thing with my psp 1000 with the ps3