Build an iPhone app connected to our PHP site

We are looking for someone to build an app for our web-based software. The site has a working database and full functionality (MySQL database and PHP based site) and we want to bring some of that to the app. I need to work with someone who has built an iOS app before and knows exactly what is involved in getting it done and loaded into the app store. My business partner has designed all of the screens for the app, and one developer started to make these in Xcode but is too busy to finish them off. I will attach his work when I have it sent over. The app is for a proposal system that already exists. Users can send a proposal and they receive email notifications when it has been opened/signed. They can also view tracking for each page view. We want to bring this to the app so that the email notifications take on the form of app notifications, and it will display a timeline of all their proposal activity (i.e. when a proposal is sent/opened/signed). I have attached a specification which details the various pages we need and where relevant, how they link to the site. I have also included all of the screen designs so you can see what you'd be working with. Please feel free to ask me any questions you might have or pop me a message if you want to have a deeper chat.