I used Coastal Insurance to find insurance. They do not sell insurance themselves, they do all of the legwork and find the insurance company for you and give you multiple quotes. It saved me so much time! http://coastalinsurancesolution.com/homeowners-insurance-quote-brooklyn-ny/... more
You have a 2 fold question - one is insurance, to confirm rates and values please try David Salem, Vice-President at Insurance Solutions - firstname.lastname@example.org I also found values and costs to differ on policy and reality but he can explain how they get to the values and replacement costs.
Your other question requires a contractor and estimates, perhaps an architect as well. email@example.com is a talented & knowledgeable architect, but finding a qualified builder is important - get quotes... Hope this helped.