Q. How long will it take?
A: How long it takes is related to the question about how much it will cost. The time is dependent on work, and work is dependent on scope. You're responsible for the scope, but we'll help you define what that is. There is an axiom in software development and engineering in general: There's cheap, fast, and done right. Pick two. It is impossible for all three to be true. The answer to how much it will cost is with you, the customer.