I just purchased a 94 Altima GXE with 105k miles on it, automatic. Runs great but about 3 days after I got it I pulled it into the garage and it leaked coolant all in the floor. My dad and I looked at it and the leak is up above the water pump. He took it to a local Nissan dealership and they said it was the Intake Gasket (PN# 14302-1E400). The gasket costs $4.18 but an estimated $530 in labor. The coolant looked brown, so I think someone may have tried putting stop leak in it or something. We used radiator flush, then put Super Stop Leak in it, but it only slowed the leak down...So I have a few questions:

1. Does this sound like it could be the problem?
2. Does anyone have instructions on removing the head and replacing the gasket?
3. What else should I replace while I'm doing all this (other gaskets, timing belt, etc)?