Are you talking about the summoning stones, or the runes that you need to send the dragon on it's death march? The runes come from defeating shamans and champions during seiges. You have to find the summing stones on the field before the siege starts, then take it to the stones to summon the dragon first. I don't know of any other way to get runes for making the dragon attack other than during the sieges.
http://img122.imageshack.us/img122/1060/amazinghn2.png Noooo! Not Patrick Swayze! You can pull through it buddy!