I want to prepare for CPBA and want to know how much time it generally takes to prepare. Also, what resources other than Business Architect Essentials and Mock test on Pega Academy can be availed to prepare for the certification.
as a rule of thumb you should do the exercises at least 2 times, better 3-4 times, until you feel really sure about what you're doing. Also the practice exam is meant to show you weak points. It's up to you how quickly you can cover these. So I'd say after taking the 5 day course you'll need at least the same time again for exam prep, varying with your prior knowledge / exprerience.
And there are no other sources or materials for the exam. If you find any it will be a scam offer of very questionable quality.