Search user input data filtered by post (zip) code / suburb

I am wanting to have forms for visitors to my site to add information including an address.

I want other users to be able to search the previously entered data and search by different criteria including suburb / postcode (zipcode).

I have a database supplied by Australia post which includes distribution areas so I want to be able to provide results filtered off this database so additional results from nearby suburb or postcode (zip code)can be included in the results.

Is there a plug in which can already do this?

If not is there a plug in which can be easily modified to do this ?

Thanks in advance.

Glenn