Go to Google Reader, then click on the gear icon at the right of the page and choose Settings. Click in Import/Export. In the Export your information section, click on Download your data through Takeout. Follow the instructions to download your data.
When you download the data, you'll get a ZIP archive. Double-click it, and look in the Reader folder for a subscriptions.xml file. You can use that to import your feeds into other RSS readers.

