Clash of Clans Clone Development

We are looking for highly skilled and proficient development team that can provide an integrated solution to an online game similar to Clash of the Clans. We are open to development in a framework such as cocos2d Unity 3d. All source code will be property of the company, not the developers. It may not be re-used for future projects. We have graphics, we need only the development of multi-level (based in XML) Game center configuration, in-game purchases, buildings logic, the "single player" quests/levels and timed messages/prizes/ads. Minimal original content needed. Game mechanics, genre (strategy), will be based need to be based on Clash of the Clans with alterations in design, theming, interactions, game elements to be provided by us. Please make sure your estimate includes 3 weeks (part time?) before and after launch of tweaking and updates to user-experience, balancing and details. Please ensure you look at Clash of Clans prior to submitting a quotation on this job. Please note the "hardest" parts of developing that game and what would be saved removing that functionality in order that we know you understand the entire game concept.