Pool of Radiance - Valhingen Graveyard Cont'd

I'm ready to battle the vampire in the graveyard. I found a cross-shaped crypt with a scroll and a coffin. The scroll was recorded:

Journal Entry 43 - history of the last time the vampire was defeated

Basically, it sounds like I need to destroy the coffin, sprinkle it with holy water, defeat the vampire in battle, and use an oak stake to finish him off. In preparation, I bought holy water from town and a wooden holy symbol. I don't know that the wooden symbol is what I need, but I'm going to give it a try.