Your use does not seem excessive from what you describe, I used to
double that usage from your description. You need to do your own energy
audit to see what you realy use, a Kill-A-Watt and good clamp on digital
amp meter is a good place to start. I would guess upgrading to 200a you
are looking at 1-2000$. Your voltage drops could be individual circuits
being overloaded. Maybe you just need things split up and a few new
circuits run.