The rules for the Warhammer are included in the rules of Sisters of Sigmar.
I was playing a priest from the Protectorate, who is a little stronger I believe (not sure though, coulldn't find the rules for the HS), and either charged right into the mess or had him back up my fighters with hearts of steel from the second row of fighting as I had to face some nasty ogres. But I think it all depends on what spell you got.