have a look at this:
that file contains info on software raid devices and will tell you + us if a member of your raid0 (disk/partition) has failed.
an example output can look like this:
Personalities : [raid1]
md1 : active raid1 sdc2 sdb2
78011520 blocks [2/2] [UU]
md0 : active raid1 sdc1 sdb1
136448 blocks [2/2] [UU]
unused devices: <none>
in your case you need to look for [UUU] or [_UU] and the likes. they indicate which device has failed. in the example above [_U] would indicate that member /dev/sdc2 of /dev/md1 had failed. if you end up with [UUU] it's "just" a corrupted filesystem. fsck.ext2 should take care of that if recovery is possible at all. if the raid0 itself is degraded partial recovery (just chunks of data) might be possible, but that is up to experts to decide.
next time go for raid5. harddisk are cheap and recovery from a failed disk is possible.