I found Barron’s prep guide to be much, much more helpful than the Princeton Review as it goes more in-depth. You can probably find copies at your local library or on Amazon etc. The practice tests tend to be much, much harder than the actual test, so don’t focus as much on the score but learning the content.
Also, I would recommend buying or borrowing the official SAT subject test for Bio review guide made by CB (available on Amazon etc.) as it has official tests that are helpful to use for review near test day.
Hope that helps!