How much would that iPad app cost?

Hey, Im ready to get my iPad-app build by a company. To be better prepared for the situation I would like to now how much it will cost. Its an app close to flipboards complexity for the iPad and I finished the design as where as it "only" needs to be programmed. Even though they might want to change a bit of the design, I am sure the basic design is finished. How long will it take the company/persons to build it and how much will it cost. My hope/guess would be around $4000-$8000.