We went to Australia on honeymoon but the wedding was done on the cheap. We didn't buy new clothes! We wore clothes we already owned and saved a lot of money. Getting to Aus was expensive though but once there, not so bad.
Have you thought of Croatia, Estonia or Poland for a holiday. All lovely and inexpensive. Or Cornwall - you can drive there and take dogs if you have any. We go to Cornwall quite often, would like to live there (Should have moved down when we left Scotland!) There is diving, surfing, decent beaches and quiet bits, even in the middle of the summer hols.
Have you considered a plan B of getting away for a long weekend after the wedding and then having a nice (cheaper) holiday, off season? I am assuming by your window of dates that you might be teachers or some such though.
Congratulations on your impending wedding :-)