(UPDATE: Google has added an export feature to the new interface: http://www.uni.edu/its/support/article/1677 )
- Login to your UNI email account at www.uni.edu/email 
- Click on the "Groups" link at the top of the page.
- Make sure you are using the old Google groups. The export functionality is not yet available in the new interface. Click here for instructions on switching between the two. 
- Once you see a list of your groups in the old interface, click on "manage" next to the group you'd like to view.
- Click on "Management tasks" in the menu at the right.
- Click on the "Manage members" tab.
- Click on the "Export member list" button.