hi shashi,
In my opinion der is not any need for doing level 3 questions as dese r not required in d recent jee papers so i will advise u to make ur concept very clear rather dan wasting ur time in doing tough question as from those questions u will learn nothing but just waste ur time.....
level 2 questions r really gud for d preparation n i wud suggest u dat u can get from d study material of any leading coaching institute n i wud say u to stick to any one u like most or d one who u trust most as dey will provide enough materials for preparation n nothing else is required...
if u hav extra free time , den u can utilize it by reading ncert books as it will help ur board preparation n also dey r important for jee .
I wud suggest u dat d materials u planned for using for d last tym is quite authentic n u must stick to it rather dan looking for more as in last time u hav to revise ur notes rather new questions n i wud say u dat always try seen questions at d time of exam...as if u start doing a new question n u r n't able to do dat den u wil get depressed so please stick for one study material as dey r complete in demselves.