Cracked head gasket

Hi,
I have a 2002 Buick Century Custom addition with 149,000 miles. The car had a coolant leak and I took it to the shop, they said the leak was coming from the intake gasket valve. I got that fixed and the mechanic said I had a cracked gasket. When I drive the car the needle for the temperture would jump from being in the red to where its suppose to be for normal tempertue. The car started doing this a couple of days before I took it to the shop and it still is jumping around. I want to know would it be worth getting the gasket fixed?