Build host and manage an autoresponder

We need a robust auto responder built that has an upgrade feature for our members to upgrade from the free version to the upgraded version possibly having 2 versions free version 1. letters would be sent out from leads that were captured from our capture pages 2. the members can import 5 or so people a day upgraded version silver 1. members can import names list with valid IP addresses 2. members can edit the emails upgraded version gold 1. all of the above features plus 2. members can setup new email campaigns for any company they would like we need this built, hosted and managed ( keeping it white listed as best as possible ) I have a few samples of what we are looking for