I can not recomend these courses enough. I've done loads of them over the years and, as a nurse, still have to update my life support (CPR etc) skills yearly. Definately worth doing.
Both St John Ambulance and Red Cross have specific courses aimed at dealing with children. The adult courses do touch on giving children CPR and EAR but don't always give you the opportunity to practice it as much as adult CPR so please consider this when chosing your course.
My Mother's Group (which is run by the local council) includes CPR as one of its sessions - perhaps call and see if your local council has anything similar lined up. We are not being charged for this.

HTH

MG

P.S. It is recommended to update your CPR yearly as the National Resucitation Council revises protocol yearly and makes changes based on what is CLINICALLY PROVEN to be most effective (you can also look up changes on their website).