Sorry for the delay in answering.
You should backup your disks to another using dd. That way, you don't just have one go at getting your data back.
I suggest you read the man pages to make sure what each option does in mdadm.
Best of luck in getting back your data. You should have had backups and you should have changed the disk as soon as it failed or at least had a spare disk that would have started rebuilding the raid as soon as there was a failure. A good option for you might have been RAID6