customizaton of a2b for web dialer voip service

a2b customization and web integration for web dialer. Back end will be Asterisk or any other option. a2b can be used but not mandatory . Web dialer should use iax or sip with g729 or G723 . passthru is fine . MUST BE EXPERIENCED - customer can instantly see rates by typing destination. if they type "in"....all suggestion with in ...like india , should be shown similar to google - can sign up or login to their account , - can make calls using webdialer. No downloads - Web dialer should show balance of customer - Web dialer should show current rate per min / remaining minutes - balance should decrease in real time - Nice looking but simple website. preferably web2.0 look - configuration of payment gateway for paypal , credit cards to recharge account - should be compatible with smartphone / tablets browsers ( confirm if its technically possible or apply or android put some restriction