Build me a web application

Current draft for software requirements :- Project components 1. An application deployed on the [login to view URL] is not much of a [login to view URL] need it alive till the end of Sep..maybe windows Azure..needs to be free to keep cost down ?? Trying to keep cost to a minimum so prefer free 2. User could be a student or [login to view URL] a login/registration screen on opening the website(basic simple but pretty) with Username and password(and code as mentioned in point 5 ).authenticated against a hash from DB or any alternate standardised procedure. 2.2 User provides Fname,Lname,email,student Id during registration..stored in backend 2.3 Forgot password component via email. 2.4 safe against injection,and garbage registration data etc 3. All Account creation approved by a separate admin account. 4. Teachers can create a wh*teb*ard session and then send out invites via email to students(before or inbetween a session) after they themselves are logged in(invite screen on the screen).Email includes temporary invite codes or direct link(has a a 1 hour life). 5. Students can login to system using these invite 'codes' or link..the users logged into this 'classroom' should be visible when running a classroom session.. 5.1. Atmost 20 students can login at a time (include scope for more..50 or so) 6. Once logged in,students/teachers presented with a 'wh*teb*ard'..teacher has initial control. 7. wh*teb*ard is like a freehand drawing board.. but needs to be an 'HTML canvas' element(absolute requirement). 8. wh*teb*ard should also have a simple toolbox along with it..simple one like ms paint..with tools like pen,color,eraser,etc t (and feautures like undo redo if possible) 9. at any given time only one user student or teacher can have control of the wh*teb*ard .Teacher can take over any [login to view URL] needs to be granted by other student or by teacher. Release of control returns control to teacher. 10. current state of the whiteboard is shared by all users live.... 11. the application should provide this data via web services. 11.1 would it be possible to share audio?? without any lags or errors? 12 Window also needs a basic live chat feature for all participants in a classroom..(encrypted and decrypted using AES or any other fast way if possible). 13. Needs to be made in c#,uses webservices, and hosted on a web platform and other options as mentioned in the list above Budget is a constraint