From your mail, you said you have shimmed through PMBOK.I must be frank with you,some people READ through PMBOK more than 2-3 times.
The exam preparation is on individual basis,it depends your schedules activities in your work place and other busy areas.
For you to have confidence,you MUST read not skim through the PMBOK(''PM Bible'') nothing less that twice,read Andy crowe for ITTO(not memorize but understand) read through Rita.
All the above my take you full whole month or more.
Then you may practice question along or after you are through.
Cornelius said you practice and practice until you are sick of it(i practiced over 2,000 questions before my exams,yours maybe 1,000).
For any other questions feel free.
Thank you.
Gbolahan, PMP