You should never put yourselves in a financial bind because of someone else. You must always put your family first. I think it is rude to ask people to pay that much money for anything.
Does this mean that the parents have to fork out this money also??
I think if enough say no they will either have to rethink their plans OS or just have a very small wedding. Don't forget that there is flights, accommodation, insurance, clothes, food and transport to consider and I'm sure you don't want to fly and spend that amount of money for a couple of nights.
Hopefully it will be later rather than sooner and you will not be allowed to fly and your DH will want to stay nearby in case you go early

Think of the wonderful holiday you could have in OZ with that amount of money