@guineapig,
Your iCloud documents are visible under 'Mobile Documents' in your library (the one you can access by holding down 'alt' when you hit 'Go' in the menu bar whist looking at your user account in Finder).
Access that and see if Time Machine has backed this folder up. In which case you are lucky!
It works for me, but I am not sure if this is because I made an alias pointing to that folder on my desktop. There is some anectotal evidence (somewhere in this thread if I remember correctly) that Time Machine normally does NOT back up this folder. In that case, set up such an alias and at least you are safe for the future.
iCloud behaves completely unpredictable when machines get added or modified. I lost all my iCloud files last year when I added my new MBP. when I upgraded to Mavericks last week, there was no loss of iWorks files. But, now that iBooks is on iCloud, I lost quite a few .PDF's which I had on iBooks on my iPad. Unpredictable as I said before....😕
By the way, if you use any iWorks application in OSX, be aware that the 'upgraded' versions of Pages, Numbers and Keynote are very different from the ones you currently would use and have a lot LESS functionality! And once you have opened a file in the new version, it can no longer be opened in the old one! It may not effect you negatively, but lots of users are livid about this 'downgrade'. There are several threads in the user forums that detail the changes in each of the iWorks apps, read those BEFORE upgrading!! ⚠