Okay, so today I just started playing the DLC, "Dawnguard", and I got to the point where you have to rescue the Moth Priest from the Vampires. I did that but I saved after I did a bad thing without realizing it - I made him a hostile. So when I continue on with the question, "Prophet", I can't complete it because when I enter Fort Dawnguard, Isram and the Moth Priest and other Dawnguard soldiers attack the Moth Priest on site all the time. I can't complete the quest due to this stupid glitch but I think I have a solution, I need a Master Illusion spell called "Harmony" or any other spells to make hostiles friendly for a period of time. I'm level 81 by the way, all perks used and none in Illusion or any other type of magic. So that brings my to ask two questions:
1.) Where can I get buy these spells (Master rank)
2.) And will I be able to use them?
If not, than can I enchant armor so Magika is increased or Illusion spells cost less to use, than would that work? If someone can help me out, I'd appreciate it very much!
And not like this is important but my character is primarily a Thief/Assassin class so nothing towards Magic was increased.