I'm using the Oxford CD's (OAA CBT) and I can highly recommend them! They can save you a lot of reading, thus time! Not cheap, I know, but IMO worth every cent.
Regarding the QDB, if you want to prepare for the exams in a time efficient way, check out the following link:
ATPL-Coaching - Efficiently Pass Your Pilot's Written Exam for JAA ATPL, CPL, or IR! ICAO Language Proficiency Test up to level 6!
Good luck!