Additional functionality to existing PHP website

Need to add a free registration option to an existing web directory site. This will be a simplified alternative to existing paid registration system with limited capacity. The website is written in PHP, admin resource of the site is in JS. Description: At the registration page 2 options will be available - paid subscription (existing) and free registration (need to implement) 1. At free registration page all the same personal and business info as with paid subscription is collected. A confirmation email is sent with user name and password. 2. When logging into user profile - the user is first directed to the page with offer to upgrade to a paid subscription. Information that will not be publicly displayed because of reduced functionality of a free profile will be marked as such in the user profile. 3. Search results will be displayed as follows: paid subscribers in alphabetical order (links to their detailed business info pages), then free subscribers in calendar order (from latest updated profiles down to the earliest) - no links, just the basic business info in the search result line. Search for paid subscriptions is already implemented. 4. Every certain period of time a reminder email is sent to free subscriber to upgrade. Free subscriber must log into his profile at least once every 2 months in order to stay active. 5. On the admin side - the same access to free subscriber profile is implemented as to paid subscriber. There will be a separate tab for the list of free subscribers. 6. Free subscriber should be able to upgrade at a simple mouse click. 7. I suggest adding a flag to the existing database table to determine if the subscriber is paid or free.