University Management System

We are looking for creating a web based solution for a university with around 2500 users to start. This platform will help us keep track of all student information, allow administrators to manage users, let students pay their course fees online, and showcase our faculties, departments, courses, and upcoming admissions. I want the solution to be easy to use and accessible. Can you suggest the technologies you would use to develop this application? Also, how long do you think it will take to develop, launch, and test? The design is already done, and I can share it with you once you're on board.