Am I right in assuming that RAID md0 has members sda1 and sdb1, and RAID md1 has members sda2 and sdb2?
If this is the case, just run the following command to re-add the missing members back to their respective RAIDs:
root# mdadm /dev/md0 -a /dev/sda1
root# mdadm /dev/md1 -a /dev/sdb2
Before you do the commands I've listed above, please post the output of /proc/mdstat. To watch what's happening with the RAID, as it rebuilds, or just in general, issue the following command:
root# watch -n1 cat /proc/mdstat
To kill this command, just press Ctrl-C.