looking for plugin recommendations to support selling & supporting software

I’m looking for a plugin or set of plugins that will provide the following functionality to sell piece of software on a yearly subscription basis and provide a customer support centre and user community. Below are the major requirements

• allow people to register on the site
• registered users can get access to more pages and posts
• signed up users can opt into newsletter sequences (autoresponder)
• I can have multiple mailing lists that people can opt into or out of (currently using comm100 email marketing)
• people can pay to upgrade their membership using PalPay website payment or creadit card (currently using buttons from PayPal)
• I can create additional fields for the user e.g. license ID to their copy of the software and activation key or other information
  they provide or I enter (some of these fields should be editable by the user, others read only and others visible only to
  me)
• I can search for people based on these fields e.g. show me everyone who is using a specified version of Office or people
  who have not renewed their subscription
• they have a mailbox I can use for support (messages are also emailed to them)

I would be grateful if people could either respond here or in email to info@emarkingassistant.com Free is best but if the value is premium plugins are also of interest.

Peter Evans
eMarkingAssistant.com