Calendar-driven reminder system

We host a gift shopping site, and need a developer to add a calendar-driven reminder system: The site design is done by us, and we already have our own ecommerce engine (CityStar SecureShop, PHP/mySQL). Our client wants to establish a database that will be member driven. Once someone purchases something, they can be added to a membership list that will have their personal information, and an option to receive a newsletter, and include an area to enter reminders (birthdays, anniversaries, etc.), and the ability to send out an email reminder before that date comes. What client hopes to do is set the email up to include the reminder information. Example: "Wilma, your husband's birthday is September 9th -- That’s two weeks away! We have great gifts to send to him...." etc. etc. She also wants each member to be able to keep addresses on file for each person they buy a gift for, and the option of adding a person to their list, as they make purchases. SO if they order again next year, for their mother, the database already has mom's shipping info.