Is switching from one author to another in tax a gud option

hello friends,

i am in ipcc level and going to give my exams in may 2013

i have not studied the new ammendments and i think that i should study the whole tax from another teachor..

but seeing the time left i am confused as to should i take the new update book of the author i was previously studiying with or go for the whole new class from another author...

thanks in advance....