Pontiac Grand Am Gaskets

Engine Mechanical problem
Pontiac Grand Am 6 cyl Two Wheel Drive Automatic 71,000 miles

Went to have a coolant leak repaired and after a pressure test, they told me that the intake gasket was leaking (which they told me is fairly common to Pontiacs at around 60,000 mi). Further, they told me that the head gasket was leaking and that due to its location, this was something that they would not be able to repair. They said that it would involve disassembling the engine and sending parts to a machinist and that I would likely only be able to have this fixed at a shop that deals specifically with motor problems or at the dealership. Worse, they told me that the coolant is mixing with my oil and is leaking into the motor and that I should avoid driving until it is repaired. I was told that if not repaired, this could cause irreparable damage to the engine and that with regular driving and no repairs I can expect the car to "die" within a few weeks. I was advised to seek a second opinion about the head gasket, and was shown evidence of coolant/oil mixing. Estimate for the intake gasket: $1000. Guesstimate for the head gasket: $1000 - $3000. Total = $2000 - $4000. Given the make and model, does this seem reasonable?