I don't think you should be having that much of a problem. Maybe you need better armour (or more
restoration potions). The low resistances shouldn't hurt too much; there is a bug (fixed by the
patch) that can result in negative resistances.
What class are you? The warrior's spin attack is great for crowd control, as is the mage spell Burning Wall (encircle a group of opponents in it) or Hell Spikes (at higher levels). For the holy grail, you can avoid fighting by tossing the grail until you get it to the door, then picking it up and leaving immediately.
Perhaps check out the topic below, though you have not gotten to that fight yet (it is after the dwarves in the burial grounds), so it will contain some spoilers.
Chasing Josie... techniques for defeating Josephine
