My 10-yr-old house has poor AC in the top floor (basement, main, top floor). I checked the attic and found it to be 130+. The AC ducts for the top floor go through the attic. They are insulated, but I wonder if cooling the attic will help.

The attic ventilation is also very poor. For ~2400 sq ft, there is one gabel vent on the south about 1 foot sq. There are three skylight vents, but for openings, the builders simply pounded a fist-sized hole in the roof where each vent was attached.

I've cut the skylight vent openings to match the size of the vents. There is about 2 feet deep of insulation sprayed on the floor. I'm wondering if 1) do I need another gabel vent on the north side of the attic, 2) should I install an attic fan, and 3) would adding rolls of batted insulation along the roof help?

In other words, I'd have dual insulation in the attic: the stuff sprayed on the floor and rolls up over head... (I live out West.)