PHP mod (repost)

I have a php site that is a calendar with religious events on it. These events are from roughly 10 religions. The Calendar can be used by universities and other entities to add their own events to it after they subscribe. It can be seen here. [login to view URL] I need a few modifications to the Admin section of the site. Mod 1: Customers have access to months for which they have not paid. Presently a customer can buy the use of the Calendar for a year as an example. They add events to it which appear for the entire subscription of a year. The events they add do not appear after the end of the subscription, which is good, but the "general" events, found on all the calendars do appear. I want these to not appear as well. In otherwards, after their subscription is over, the Calendar is blank. Mod 2: I want the ability to add more months to a customer without adding more cost to customer. When a client subscribes, there is a drop down box to enter a year or 3 years. I want this changed to a Start date and an End date. The reason is that a customer may buy the calendar a couple of months before the end of the year and I want to be able to add the months for free. Mod 3: Adding an Class called "accommodations" in the drop-down menu on the events edit page and also adding a new column to the exported data.