Pretty sure Niera is vulnerable to Undead Slayers.
Sampire weapons i would suggest if you dont have 1.25 ss then add enough ssi to reash the ss cap.
Radiant scimitar for whirlwind when you get more then a couple spawn on you the MS will not handle.
Broadsword for AI or Ornate Axe for just massive burst damage.
Bload oath is tough when she cast it unless you have 120 resist and will make it tough to work through it.
Mana Leech, Stam Leech and DI, HLA and HLD are the most critical if you have Mace and Shield glasses then you get a boost of the HLD.