Alright, I can tone down the vamp magic then, if you want a more realistic thing. Or can go the full blown -change into a bat- type vampire?

Just let me know.

I usually base my vampires loosely off the rpg 'vampire the masquerade' where there are different clans with different abilities but they all work off spending blood.

P.S! You need to watch some vamp shows, start with 'interview with the vampire' then follow up with 'queen of the damned' ;)