An MCQ website for medical students and junior doctors

I would like to set up a medical revision website in which the user can log in and do medical MCQs that I have written. They should be able to select from a menu the various subject areas they want to revise and also select how many questions they wish to do in that session. There should be a timer included which times how long a particular session takes to do. Once the user clicks an answer to the question, they are told if they answered incorrectly or correctly. An explanation of the answer is revealed below for them to read. Below this, a statistic for the question is shown which tells them how often this question is answered correctly. At the end of their session, they have the option to review their questions the number they answered correctly and incorrectly are recorded in their profile. They will have the option to compare how they are doing to everyone else. I would also like to include a quick fire mode in which the short questions with 3 or 4 options are presented and the user selects an answer, is told whether he/she is correct and a new question comes up. The program should remember if the user answered correctly and if not then the same question should be repeated 3-4 questions later until the user answers it correctly. I would like to have easy access to website to add to the MCQs and change it how I wish.