Tamil word doubts

Hi, I wanted to know, in tamil how do you call 1. A priest in a temple? If you wanted to ask something or say something then how do you address the priest? 2. If a lady is elder to you then you call akka. But how do you call a lady your own age or not too young and not too old if you don't know their age..say like in a supermarket or vegetable shop etc? Thanks