if your not sure where its leaking from, I would do a compression test and leak down test etc, or have a shop diagnos it,
It is not possible to say if the motor needs rebuilt with out know how many miles are on it and if it was regularly maintained etc etc. Head gasket failure dosent necessarily mean the motor is junk. many times you can just pull the heads have them checked out and freshened up. Or maybe consider upgrading to better heads at this point. My old motor had 125000 miles on it when i added thumpers ported heads and a comp cam and other items. I recently built a new motor and swapped it out.