For subjects other than IDT and DT, there should not be any major changes. Go for the Jan 13 edition. Wait sometime for the newer edition of IDT and DT and do those. In any case if it doesnt come out in time, go for the Jan 2013 edition itself and for important topics refer the newer versions that is available on BOS knowledge portal.
I would suggest don't refer the DT practice manual at all- if you are studying from VG sirs books or refering any other book with ample illustrations and practice questions. But do refer the supplementary study material that ICAI will publish.
For IDT, refer valuation chapters, CCR, CER 2002, and other chapters you find testable questions can be formed. Again refer supplementary study material.
Expect substantial questions from amendements.
Good luck.