Check my DIY :
http://www.986forum.com/forums/showthread.php?t=15522&highlight=Tiptronic
Much less than you were quoted, incl. buying the fluid pump (which is the only one I'd use - holds all the ATF at once), 17mm Hex Bit, Sealant, Gasket and Filter (s/b changed every 45k mi.).
I'd definitely say it's a pretty easy, though time consuming DIY - I'd rate it a 3/10. PM me if you have any questions