1) Go to Google Takeout and either select the 'Choose Services' link at the top of the page, or simply follow this link
3) Google now prepares your download. When it is finished, press the 'Download' button. You may need to sign in to Google Reader at this point, and you may need to press the 'Download' button again
4) Now that the file is downloaded to your Mac, go back to LuckNews
5) In the File menu, select the 'Import Subscriptions...' menu item
6) Navigate to the file Google downloaded for you. It may be in your Downloads folder off of your home directory. In the Downloads folder, look for an item with your email address followed by '-takeout'. Open that directory which should contain a Reader directory. Open the Reader directory and select the file named 'subscriptions.xml'
7) You are then presented with a dialog in LuckNews, simply select the subscriptions you wish to keep, and then accept them
You now have all of your Google Reader subscriptions in LuckNews, ready to read.