I just spent 10 days up in Yamba over christmas and there was fish everywhere in the river. Flathead, whiting, bream the odd flounder and unfortunately loads of stingrays. Also saw several school jews being cleaned at some of the ramps. We caught fish every session, varying degrees of success even when we just fished off the caravan parks jetty like everyone else. (the young bloke just had to fish everyday )
The upside for you is there are 5 or 6 quality surf beaches right at your door step to go with the fishing. If you have a boat I reckon you could explore forever.
Highlight of the trip was fishing from the jetty and having a pod of dolphins come right up to us and smash a school of fish on the surface. Close enough that we could have touched them with the tips of our rods several times. Was an awesome sight, unfortunately after a decent start (2 keeper bream in the esky) we didn't get a single bite once the dolphins went through!