Yasal Program Forum

First you should make a backup of the HDD. Boot the mac from the install DVD and use the disk utility to make a backup on a external drive.
I don�t know a free recovery software for mac except the beta version from Disk Drill (and testdisk / photorecovery of course). Also this software needs a running mac os.
If you have a second mac or access to one you can set your mac with corrupted file system into target mode and connect it to the other mac running disk drill.

When i hab big trouble with the file system after a power loss i bought Disk Warrior. It�s expensive but it�s really worth the money. Also i got a used version half the price on ebay.
You can try to run it in normal mode to fix file system errors or in scavenge mode searching for lost files.

I lost a lot of files and some of the rebuilt files don�t work. The file system really was heavily damaged.

Doing regular backups should avoid this.