Asterisk Autodial + SMS

We run a taxi company and currently have a modem connected to our computer system that rings the customers phone when the taxi arrives to pick them up. The taxi driver has a button on his PDA in his cab which is linked to the office via GPRS which in turn is connected to our computer system. When the button is pressed the computer dials the number via a normal modem and drops the call after two rings. I would like to get it so, 1: if outgoing number is a fixed line number i.e: 0207--, the call is routed through our asterisk telephone system and plays a recorded message then hangs up. 2: if outgoing number is a mobile number, a text message is sent to the number informing that cab is [login to view URL] sent SMS messages to be stored in a database & Create a contact List database for all receiepients with delivery time & Number. Also itegrate an API to send marketing SMS to contacts in the database. Changing the method of how the call originates is an option so the commands can come directly from the Com port or from the PSTN side of the modem. For SMS, i would like to use a GSM Modem connected to our server & use a mobile operator in the UK. Make & Model is subject to recomendation. GSM Modem can be connected to Windows Or Asterisk Server subject to coder's choice. Here's what I want to end up with: I would like you to create a 'Virtual' serial ports on our windows server. Then I would like you to write an application that listens on these virtual com ports, captures the dialed number and differenciate between Fixed Line Or Mobile Call, 1: in case of a fixed line number i.e: 0207--, use Asterisk Manager Interface commands to make the call, wait for the customer to answer, play a recorded message then hang up. 2: if outgoing number is a mobile number, a text message is sent to the number informing that cab is ready. For SMS Application to allow sms messages & numbers to be stored in a contact databse, & allow us to use the database & a web api for advertisement.