Wedding dilema! Need to postpone wedding but people are against it.?

My fiancee and I have a wedding date picked out (October 15th, 2011) and have started planning. Recently we found out that he has to have ankle surgery that requires a bone transplant. He is currently registered in the donor database, we are just waiting. He will be off from work for 4 months afterwards, andd there is a chance that the surgery will have to be redone (1 in 75). If this happens they will redo it, and if that doesn't take, we have to look at amputation as an option. Due to these factors we have to postpone the wedding (unsure about the outcome as well as money matters). We have told our family and friends about the postponement, and now everyone is trying to pressure us into getting married sooner (as in now). We don't want to do this, we want to wait in order to have the wedding that WE want...not what everyone else wants. My parents in particular are bringing this up numerous times a week and it's really taking a toll on both of us. Is there a polite way to tell people to back off?