critical reading trouble

hey guys.
i seem to be having some trouble with critical reading. I took my first SAT test on March on got a 520 on this section (pretty low). then i took the test again in june and got a 550. i am looking for a score in the 700 range. i am an all A student and take all advanced classes. does anyone have any prep books and a recommended reading list of books that can be helpful to really boost my score.