You can try Data Rescue 3 http://www.prosofteng.com/products/data_rescue.php
I believe that you can download a trial that will allow you to scan you drive for recoverable files and if any are found you'd then need to purchase the software for $99.00. I don't know if it would work on a formatted drive or not.
Another option would veto try a professional data recovery service but they could cost thousands of dollars and offer no guarentees.
Too late now but in addition to my Time Machine backup I keep a second that is a bootable clone of my entire hard drive.