Tell us you have a backup of the data!!
Your data is gone.
RAID is all about high availability and is not a backup system. RAID5 is really a not all that great to use unless you fully aware of the potential problems AND you make regular backups of the data.
RAID6 is better but you will soon have similar problems to deal with:
Why RAID 5 stops working in 2009 | ZDNet
Personally, I would go RAID10.