Quickbooks 2009 upgrade erased data from last 15 months

I just upgraded from Quickbooks Pro 2004 to QB Pro 2009. The upgrade went smoothly, but after restoring and converting the backup it has no transactions or items from the last 15 months. I have tried to restore from the backup file (made during the upgrade) three times with the same results. Can I get to the company file if I use QB2004 again or did the upgrade overwrite my old company file and give me a bad backup? It may not be possible to accurately recreate all of 2008’s and the missing part of 2007’s transactions.