[BlueZero]

Most of your heat loss is going to be out the ceiling. If you want to save money and only insulate part of it I would do the ceiling and skip the walls.

It wouldn't hurt to get a price from an insulator. I've heard that they can do it cheaper then you can do it by yourself. Since then buy insulation in such large quantities they get it super cheap.

I agree with Bob also on the venting. You will want to cut some vents in your attic.