Design an App Mockup & Prototype

I'm looking for an experienced user experience/user interface designer who can turn my extremely basic wire frames into a gorgeous looking mock-up and animated Mobile prototype. I want to be able to easily hand this over to a development team but also be able to use it for investor presentations. It will consist of approximately 25+ screens. I will need someone with a clear understanding and experience in mobile app design as we will need help with the implementation of screens and features that we may be missing in our plan. We want this to be as user friendly as possible so we need someone who will make improvements and suggestions, add screens where missing, refine what we have done and not just work from the plans provided. It is important that the person selected is able to provide beautiful, clean designs as they will have to suggest color schemes as well as design the app logo. I would like to create 2 milestones. One for the mockup and the other for the finished animated prototype. Payments will not be made unless the designs are to my complete satisfaction. Unlimited revisions until satisfaction is a must. Must be willing to sign a NDA and contract and stick to it If you have done similar projects please send them to me.