android school app - open to bidding

i am egyptian post graduate student,i have a small android project for mobile parent to enhance communication between school and admin, the application is native android app which mostly implemented by java using eclipse with google plugin services, i should use android sensors like :weather ,camera ,location service to push notification to parents in case of bad weather or to upload school fee receipt to student affairs and add google map with direction to school location , also android calendar should remind parent with school monthly event ,also student timetable every week end depend on parent identification, that's all how much does it cost if i need it open source for modification? How long will it takes to implement? how can i sent analysis or contact with you?