I have a raised ranch that was built in 1966. There are 2 bedrooms sandwiched between the garage and the attic. These two rooms get very cold in the winter. There is about 8" (2 4" blankets) of fiberglass insulation in the attic. The garage ceiling is finished but is insulated. I think there is only 4" of fiberglass.

Is there another type of insulation I should use or should I just add more fiberglass?