I have a 2001 Honda Civic EX with 165K miles, and just overheated after going up some hilly areas in Los Angeles there other day. Radiator was dry and reservoir was full. I put fluid in the radiator, and the car/thermostat has acted fine and hasn't been overheating at all and have done very limited local driving the past 2 days. I took it to an independent shop in LA today and they ran the car while the radiator cap was off. The radiator fluid was bubbling over a bit. They said the head gasket was blown and quoted me $700 to repair. Is this a good price for repair or not?