Customisable magazine app on Android and Windows 8

Project Description:
We have developed a customisable magazine app on iOS and a php script to fulfil in app purchases. We need a similar solution on Android and Windows 8. Details of our specifications are given in the attached file.
The deliverable is the customisable Android and Windows 8 app and the corresponding php scripts. We will ask you to use a git repository, and to publish your work regularly for us to monitor the progress of the work.
Please avoid generic bids such as "Hello, Let me do it for you." (we will not read them). Avoid posting your contact details in a private message (we will not use them, pursuant to freelancer.com's terms) . Be as specific as possible, ask precise questions if needed, and/or let us know if you have relevant experience.
We posted a similar project a few weeks ago but did not get convincing bids. This time, we are adding the Windows 8 development, and increasing the budget, hoping that a bid will convince us. Having developed the app on iOS, we know where the difficult issues are. We expect the bidder to mention them (briefly) and explain how they are going to handle these issues.
Thank you for reading!