CMS for Educational (Android app + Web based management)

We want this app for our school. We have contents written in MS Word. These include syllabus, books, some pictures on these books, some charts, class schedules etc. We need a content management system which have two sections. An admin section that we will access on laptop (i.e. website based) and user end section that is displayed on Android app and a website too. Web based admins will add contents i.e. text and graphic into system. User / students will then access it to read on both web and Andoird app. Important features: One database will be used on multiple platforms. This system will later share its database with iOS version. Some contents are for practice. These include multiple-choice questions, filling blank questions etc. Students will have option to practice these. Admin will have a section where he will add questions in database along with its answers. During practice (on web or android) student will get instant feedback of their performance on each question etc. More: We will provide entire structure detail, basic flow charts, graphics etc. Reply with 1. Expected cost. 2. Details you will need before project begins. 3. Time milestones. We would like to see your previous work. This is a serious project and will only be assigned to those who have some reasonable experience.