Radius Server with credit card authorization - repost

We're a small start up Wireless Internet Service Provider in the US. We need someone to create a Radius Service so we can capture any users who would like to use our internet service but do not have an account and bill them by the hour, day, week or month. Once the customer reach our service they will receive a credit card page where they can place an order to purchase our service. Any customer who have an account with us, once traveling in our service area, will be able to access the network without encountering this payment page. We need to prevent this by adding the customer's information to the server. These are customer's who sign up for our service. We can use the customer's 10 digit phone number to identify the account. Please only someone who can provide this service in detail need to respond.