To restore your data from a backup copy - simply select "Backup|Restore From Backup" menu item.
After you select it a file selection dialog will show up asking you to select a file from which to restore. The filename will contain the date so you will always know when was that backup created. For example - a backup file could be called "TalkingReminder-12-31-2005.backup" Simply select that file and Talking Reminder will restore up your data.