Please help me for exam preparation

I am student of CA final, i took classes for IDT in 2013 from Manoj Batra Sir and for DT in 2014 from VG sir and after that i has not even opened the books of second group. Now i m prepairing for may 2016 exams. Pls suggest me how to prepare. Do i have to buy new books? If yes them from where? I cant take classes again.And there are so many changes in both the subjects...pls help me....