Many people suggest using the following:
CliffNotes for the AP Biology exam to review Biology (
http://www.amazon.com/Biology-Cliffs-Phillip-Ph-D-Pack/dp/0764586823)
DAT Destroyer for LOTS of practice problems (especially with O-Chem as it also includes explinat explanations ions)
Then there are other comprehensive reviewers (Barrons, CliffTestPrep, TopScore, etc).
I would use textbooks from classes to go over concepts you are weak in. I got an SAT prep book to practice the math (as I felt it was of similar difficulty) and read the newspaper a lot to practice my RC (obviously you need speed and quick comprehension to do well).
As for calculator, apparently one is now built into the computerized test. As far as I know, you cannot bring your own handheld one.