Build a Dynamic Modern Multi-user Multi-functional website

I am needing to have built a website that is capable of handling nationwide usage by administration to run a vibrant business, affiliates on the back end to access customers and forms, and customers on the front end to purchase the services by region and/or type. It will need to be able to register both affiliates and customers, take payments, take orders, communicate customers to affiliates, and offers different levels of ongoing services or one time singular services to customers by geographical location and type of service. It will also need to be expandable (so we can add 'stores') as we grow geographically and by array of services.. Finally it must have a way to measure usage, and offer spots to advertise in our affiliate network.