Changing domains to wordpress

I have a website called oldquarteraccousticcafe.com and want to change it to a web press domain old-quarter.com. I wrote word press and was told that I had to get the developer involved. The developer of the old site is here and I have all of the sign in information and FTP for old-quarter.com. Can anyone out there help me?

The oldquarteraccousticcafe.com is created through publisher and uploaded with Ipswitch. We want to use word press to update

Thanks,
Confused