I just want to share my own experience playing balance druid, it's easy:
Just attack her and, when the adds begin to come, use starfall.
Then use all your cooldowns to increase your dps and don't forget to use celestial alignment to refresh the cooldown of starfall (use it when the adds come again).
When your cooldowns are ended, turn the eclipse bar to lunar eclipse and use starfall one more time.
I just needed to use starfall 3 times to kill her and all her copies but, if you have problems with your dps, use the potions and it will be easier and faster