If you want to do it properly and don't mind spending a bit of money, you can't go wrong with OEM Toyota for the gasket kit. IIRC, they have a nice upper engine rebuild kit, has the valve stem seals (expensive on their own), has most everything you need other than the few gaskets on the block, turbo seals, etc...
As for the bottom end, if you plan on doing that, you'll want to find a competent (and preferably knowledgeable about 7m's) machinist to help you with that aspect of it.