Follow the directions here to get adb and fastboot for your Mac.
http://androidforums.com/threads/adb-guide-updated-2014-11-11.443072/#post-5389081
After you unzip the Mini-SDK and place the sdk-tools folder as instructed, you get a Terminal Window by Finder, Applications, Utility folder, Terminal Window. Double click it.
Open Finder to sdk-tools folder that you unzipped. Do not select any files.
Go to the Terminal and type -
cd
Tap space.
Go to the Finder and drag the sdk-tools folder to the Terminal. Put cursor in Terminal and press return. Then in Terminal, do -
sh sdk.sh
Get the CWM.img file, copy to the sdk-tools folder.
When ready - and I'm only advising on Mac fastboot and adb, nothing else - your command will be -
./fastboot flash recovery CWM.img
If the last term for the file name changes according to the other good advice your getting, follow that.
Hope this helps.
That's if the SDK you have now is giving you trouble.
Android File Transfer on a Mac is just for moving files around.
You can't flash one recovery from another - you have to fastboot flash it.