I am an electrical engineer and familiar with these systems in general. I don't claim to be a wireless engineer with advanced signal scanning tools or anything of that nature. Your problem is similar to one I've seen many times and actually have solved in my personal properties. I have wifi reaching 4 stories inside one building and beamed 300 feet down a New York City block to connect another building with minimal loss in speed or bandwidth. I've bid $350 which will include a more detailed assessment of your situation and assistance on a few tests you can run to see where weak links are along with recommendation of hardware and placement to purchase. The main cost is going to be in hardware. That's what is lacking with the generic routers and extenders you are using now.
This is probably more than you're bargaining for but if you really would like someone to go out there and just get it all done, I could do it for $1,000. I'm living in Dallas now so it would have to be a weekend that I'm back visiting my properties in NYC. I can wire everything up and configure the satellite links and such but won't include mounting, drilling or cable routing for any necessary links since I'm not a general contractor. Should be simple to do though if you are handy around the house.