My calendar on iCloud is missing most older events

My calendar on iCloud is missing all but recurring events that happened a year or more ago. I have therefore lost these events on my MacBook and Touch, too. I have an old backup of my calendar data, but it seems that if I use this to restore iCal on my MacBook, I'll lose all newer events. Can I merge the two backup files? When I tried to use an old backup to populate my calendar on the MacBook, I got an error message that it would wipe out the data now on my calendar. I want to merge the old data with newer events. Is there a workaround that will let me do this? I imagine this happened when I moved to iCloud, but it seems unlikely that I would not have looked for older events on my calendar (and found them missing) since then.

In addition to one iCal backup, I have Time Machine, which doesn't seem to allow you to look at older calendars, and a versioned backup to an external drive using Data Backup. I thought that one of these would let me look at old calendar data, but it's almost pointless if I can't merge the data or at least have a separate calendar for older data.