What do you want to do?
Quick question, what type of auditing do you want to do? If it is internal auditing, there are lots of sources around. If you want to audit for a registrar, you must attend special classes. More than likely you will not be able to be qualified to 3rd party audit without being sponsored by a qualified registrar. For QS you are probably out of luck because QS is dying and qualifying training will probably be hard to find. For TS, most registrars are scrambling to get their auditors IATF qualified, so unless you are a current auditor for them, then the waiting list might be a long one.
Second quick question: What is your current status? If you are already a RAB certified auditor, then you might find the going easier, if not the first step might be to attend lead auditor training and become certified by RAB.
Hope that helps.