First, ensure you are using the latest version of the app (2.6 or higher).
When you are on the map after purchasing your first policy, you can tap the blue Additional Purchase icon to return to the area selector.
Highlight the area in which you need insurance and tap Get Insured to begin purchasing as usual.
Your currently active areas will show on the map with individual timers to let you know how much time you have remaining at each location.
You may also tap the new quadcoptor icon to view and access details for all of your active policies.