Kaplan and Sauders both are great. You dont have to buy both one is more than enough.. it also depends on your learning style.
I would recommend one book... and prefer Saunder. Thats my personal opinion. Two months is more than enough.. but also depends on your learning style.
I would also recommend you .. do not get carried away by others' comments..  everybody has different learning styles.
Do not panic..  plan properly.. Good luck!!