I am planing to give CSQA...but I have some queries

I am a s/w tester having 2 yrs of exp. I am certified as ISTQB and ITIL (Information technology Infrastructure Library) ...and I am lot interested to move to QA field...So my question is as I have done two certification so is it worth to go for CSQA exam to go for QA field or these two would be enough...?

Second query is that If suppose I plan to give CSQA exam ..is it enough to study sincerely only CBOK..which will help me to pass exam..or I have to study some other books also...

Post ur blog here as well as mail me at {email removed by moderator-put it in your profile instead}
Ur answer would be lot of help...