You can try downloading the trial version of the application directly from the page linked below to a disk or USB and try using that to install on your Mac. You can activate the trial using a serial number from a purchased version. While your Mac does not have internet access you will still need some form of internet access available to be able to do an offline activation of the product.
Be sure to follow the Very Important Instructions for downloading the file.
http://prodesigntools.com/photoshop-elements-11-direct-download-links- pse-premiere-pre.html