|I have some experiences about this I really just got to share...|
The data is NOT lost from the drives´ physical layers and image, when the drive is formatted. What I strongly recommend is simply going to an actual data recovery firm, that specializes in data recovery, by use of hardware instruments. I did as such. DKC Data saved everything.
It can be expensive, but is worth the effort if your data really means a lot to you. Using software is not recommended, as it gives quite unsatisfying, maybe even useless, results, and at the SAME time it degrades the quality of the data on the hard drive, making it harder to perform a proper recovery.
DKC Data saved tons of data that I lost on several drives, back in 2005, and they use expensive technical instruments to perform the data recovery, instead of just petty software. I had first got a recovery made by software that returned me USELESS, defective files, and it worsened my situation, but even though they were still able to get the most of it.
Some info of their american department: http://www.dkcdata.com/cms/main.php