Not good your drive has failed ;-{
At this point things get tricky! You'll need to get a data recovery app which you'll run from the good system via Target Disk Mode to try recovering your data files from your bad system which I would try first. You could try using Apples disk Utility Disk First Aid, I often find I have to run it a few times.
I'll warn you theres a good possibility you won't be able to as it sounds like the boot sectors are messed up. Shipping your drive out to a data recovery service might be the only option but they are expensive and likewise can't always recover things either.
Sorry for the bad news