Emal Customers According to Past Purchases

I have an osCommerce website with about 30,000 orders. People puchase products big widgets, medium widgets, and small widgets and many other kinds of widgets. I would like the ability to sent a customized email to each customer depending on what type of widget they ordered in the first place. I would like to only send out about 100 emails per day, so that the email campaign last about a year. I just want to send them a once-per-year news letter about the widgets they previously purchased. All the order information and emails are stored in the mysql database.