Costumization of joomla plugin

Hello! I have one simple sobi2 (joomla) plugin, wich store favorite entry in favorites database. Instead of one button, I need 3 buttons so user can make his choice when adding to favorites. Option must be stored in database. Now table have these fields: id | itemId | date | userId -> we need one more column with option. So when user adds item to favorite, it will store: id | itemid | date | userid | option (1, 2, 3 -> depends on wich button user will click.) I will provide code for plugin, you must just extend it with 2 more buttons.