You could respec to have a more powerfull valk. With Iron Maiden gone from CS, there's nearly nothing that can stop a zon with a tankyre.
Other options are knockback (howltusk great helm or cleglaws gloves), monster flee, cold slow, preferably combined with open wounds(boneflesh armor).
And there's always the sniping option. Don't use a valk, but lure the Venom Lords to you one at a time. You won't be able to do this with a valk, because a valk will walk towards the enemies, causing more of them to run at her(and you).