that is part of the main quest i believe, have u tried using the javelin or the 1 aedric spear ability? do u have a healing ability in bar? those should help
don't remember if you can kite those things though

that is one of the hardest fights in the game. I am glad that you managed to beat it

While leveling my Templar a got vamp around your level. Remorphed my class abilities to aoe ones. I steamrolled through to vr5 zone then went to craiglorn and pvp. I also only started leveling restore at vet because I easily healed with class only pre vt( which is not viable vet dungeons).
When keeping up mutagen and lingering ritual and aoe mobs with blazing spear and the dark flare aoe morph and the triple fireball one u can easily get your vamp ult basically every mob if they are 4+ usually I would pull two mobs just so I could hit more with aoe giving more ult and then heal/ murder with batswarm. Loved playing all the pve. Currently I cured vamp because I'm all PvP/ trials and the fire weakness out ways the strengths in cryodiil. But the vamp fast sneak is great for PvP if you do More small group stuff and stay away from keeps and oil.

I saved all my money for respecs. I leveled everything, tried things myself tried both morphs of many skills. I have respected at 20k just for a particular morph! I leveled bow and 2handed to 50. At v1 decided hey may as well not wast exp and leveled restore and sword shield. love sword shield/ restore for pve and PvP. Now after a lot of that at v12 PvP I am using restore/ bow. Do things yourself there is no best build. I say that because I use very differt loadouts for PvP/ pve/ group content. So any very specific advice will be biased towards one and likely not the best in another format.