My 2 cents :
I opted for not playing a vampire and from all I have read from other players having played a vampire - it's worth missing.
Beware the vampire ring - unless you have patched your game. It causes crashes in an unpatched game.
I don't know how to hack the save to unmake a vampire but I might be able to figure that one out - maybe.
Personally, I'd reload the game and go through the castle again. It is always faster when you're going through something familiar.
Wyv