I think now the rates are out to q1 2015. Maybe will have to wait till next year for q3 2015.
However I don't think it is too early, I planned my wedding 2 years in adv too. Mainly because we want to do it at our pace and also take adv of deals as they come along.
What you can do now is to go to the few hotels that you have shortlisted and view the surroundings. Usually they will provide you with their latest rates and a safe gauge would be to add about sgd 100 to the rates and you should be having a rough estimate of your banquet price.
You can also take the time to look at bs as well.
