Vampire Books (12th grade reading level and under

[necromancy14]

Sunshine by Robin McKinley. It has got to be my favorite vampire book to date. You might also try the Southern Vampire Series by Charlaine Harris (1st one is Dead Until Dark).  

[Kakei Setsunai]

The best vampire books would have to be any and all books of Anne Rice.

My personal favorite vamipre book is 'Salem's Lot by Stephen King.

My current favorite vampire mangas I have read would have to be Model by Lee So-Young and Blood Alone by Masayuki Takano. And of course Hellsing isn't too bad either.  

[The Goth Apple]

Oh. You've already read the only child-to-teen vampire book of which I am aware.
Why don't you just start reading adult? If the writing's a bit thick for you, just reading it will make it easier.  

[Shadowed Intent]

I believe Anne Rice may be a little complex...

But i personally think the Darren Shan saga would suit perfectly
its great!!! and Mr Crepsley is the most awesome Vampire ever!  

[j3ll0_m0nk3y]

SweetBlood by Pete Hautman was always one of my favorites. Vampires: A Collection of Original Stories edited by Jane Yolen is great if you are more interested in learning about the various legends behind vampires as we know them today. And even though it may take a while to read, Dracula is an absolute must for any fan of vampire literature.