Repair or recover drive from recovery mode
there may be no way to rescue the system without reinstalling Mac OSX.
you might look into booting into single-user mode
that said, to the extent you care about un-backed up data on the hard drive,  it might be wise to recover files BEFORE trying to reinstall/recover further
I have had good luck with DiskWarrior
You MAY be able to boot the broken disk/laptop in "Target Disk Mode" - if it has Firewire, if you have the cable, and if you have another Mac with Firewire to attach it to.
Failing that, you or a person with appropriate tools could remove the internal disk drive, attach it to a USB/SATA adapter of the appropriate kind and use DiskWarrior on it.


Good Luck!