Bank ATM system

I need to provide a complete design for the bank ATM (teller machines) system including the software and hardware type of LAN, WAN, and the actual ATM machines.
The bank has 11 branches, and wish to introduce banking services through the use of ATM kiosks. Two ATM machines in each branch to be connected to their central data processing center at the head quarter. The response time and the bandwidth requirement is given, but I am not sure how to tackle it, as the requirement for brand new setup which should include all software and hardware execept the central database which is currently in use through cash registers.