head gaskets, etc.

I have a '91 3000GT with the 3000 24 valve engine. It started to leak a little bit of antifreeze on the garage floor last winter, so I put stop leak in it to hold off until the weather warmed up. Last night, I started to take it apart. One of the head gaskets is / was leaking. I also think the cross-over pipe from the water pump to the t-stat housing was leaking. Anyway, I need some specs as far as head bolt torque, how to time the valves when I reassemble it, where is the best place to buy gaskets, etc. Anybody help?
Abe