Call back server installation - India

I need call back server installed for following functionality. System will place a local call within india and a call to international destination and conference them It will maintain billing procedure The calls will be originated on request from an incoming call from international destination The incoming call number will be logged, credit checked in the database and a call originated from India to the incoming call number. Similarly local call will be placed and conference done with incoming call number. Please send bids with suggested hardware and software requirements as well as qoutes for installation, software and hardware what ever you can provide. Rest you mention what you need to be provided by our side.