I think you are out of luck, I don;t think you can download it from anywhere else.
Maybe also look into http://cord.sourceforge.net
Why don't you try downloading it on your computer and see if you can extract the file from the download? Right-click and show package content.
Get the Remote Desktop client. Follow these steps to get started with Remote Desktop on your Mac: Download the Microsoft Remote Desktop client from the Mac App Store. Set up your PC to accept remote connections. (If you skip this step, you can't connect to your PC.) Add a Remote Desktop connection or a remote resource. Start quickly with the most recent versions of Word, Excel, PowerPoint, Outlook, OneNote and OneDrive —combining the familiarity of Office and the unique Mac features you love. Work online or offline, on your own or with others in real time—whatever works for what you’re doing.
PS: Is that: https://www.microsoft.com/en-us/download/details.aspx?id=465 the right client?
I can't test it since I don't have a MAC at work.
or this one: https://www.microsoft.com/en-us/download/details.aspx?id=18140