[Pirengle]

Might be easy just to rest and have Viconia and Aerie memorize some Raise Dead spells.

Did you also try using what Elhan gave you in the main chamber down there?

I second BaronKnight and the logjam idea. Cast chaotic commands on Keldorn, give him the amulet of power, and put some hardy summons around him (aerial servant, animal summoning 2, hakeashar, etc.). Let all the inhabitants group around Keldorn trying to hit him. They can't level drain him, and depending on his setup he can be hard to hit.

Meanwhile, have other fighters (like Minsc) whacking on the crowd through the safety of the wall of summons. If Minsc has a two-handed weapon, he can swing right over the summons and hit the vampires, while the vampires have to get through the summons to get to Minsc.

Let everyone else plink away with missile weapons or unleash a magic barrage. False Dawn and Sunray can be put to good use, as can a well-placed Fireball or Skull Trap or two.