Any lawn pro's with some advice?

A nice sand-topsoil mix works really well for filling low spots. Go to your local contractor rental store and rent a small asphalt roller and roll the crap out of it then rent an aerator. Seed the areas with new soil and rake in then spread some 12-12-12 fertilizer over the entire lawn.
The lawn rollers you fill with water work but they don't even come close if your lawn is really bad. The great big concrete work the best but are a ***** to move.