Hi Bridget,
I’d suggest you do the steps below first:
Contact Melbourne IT and change the name server to Melbourne IT first.
You can refer to the following article: http://community.office365.com/en-us/wikis/administration/transition-information-for-former-office-live-small-business-customers.aspx#Transfer%20Custom%20Domains
After you finished the first steps, please let me know the result so that we can assistant you for the next steps.
Thanks,
Vivian Wang