If you have all your photos backed up to your time machine, you can access it by clicking on the Backups.backupdb folder, click on the "computer name" folder, click on the backup folder from a couple days before the day you did loose the photos, click on the "computer name" again, click "Users", click on your user, Click pictures and your older iPhoto library should appear in there.
Thats how i was able to fix mine when that happened to me once.
If that doesnt work, then good luck finding another way...
That's not the way one should restore from Time Machine. To restore a library from TM go into the Pictures folder and then launch TM. Once in TM go to the date needed, select the library in the Pictures folder and use the Restore button.
Click to view full size
Since TM does'nt backup files that have not been modified or are not new dragging a library from the .backupdb folder that way could result in an incomplete library. To assure you're getting the full library use the method above.