http://www.itjungles.com/iphone-tips...of-backup-file
This should get you started for recovery of the encrypted password on your master backup file. Instructions are given for both PC and Mac systems.
The PC version requires the use of a demo program that will only give you the first 2 letters of the password without paying the upgrade cost. Most folks that use this "password cracker" can usually deduce the password from the first two letters.
Don't be too hard on yourself. You'll get the data back.
Good luck. Feel free to contact me if you need additional help. Jake