Hmmmm...
I went looking for my address book data and it was sitting in...
~/Library/Application Support/AddressBook/Sources/{lots of hexadecimal crap}/AddressBook-v22.abcddb
I looked in "Time Machine Backups" and browsed to backups.backupdb. I opened the file and looked inside for a recent data. I picked 2011-11-26. Once inside I opened Macintosh HD/users/{me}/Library/Application Support/AddressBook/Sources/{same hex gibberish}/AddressBook-v22.abcddb
In your case, it will probably say AddressBook-v21 or something. Option click that file, pick copy and paste it somewhere you can get to it later. Then see if Address can "import" from that file.
You definitely don't want to use the Time Machine app to restore this file as it will overwrite your empty but good one. You want to go behind Time Machine's back and copy the file somewhere you can use it to try to "import" your contacts.
While you are in there, be careful and CHANGE NOTHING, only copy what you need! When you are done, eject the Time Machine Backups.
hope this helps...