unfortunately the exam takes place twice a year on fixed dates.. the only way is to extend your stay till your next exam on September.. for the exam sources, I studied the whole APHA and the last 22 chapters in the CPR.. try to focus on APHA! if you study it very well.. you've got the exam guaranteed.. focus on section 3 and 4, I didn't study neither calculations, medicinal nor pharmacokinetics! so don't give up..