At the lower border of the map, right next to McDonalds, you can see the Neucölln Karree, which has (among other shops) the shops owolf mentione: A large EDEKA, an ALDI, a Sparkasse ATM, etc. Should be easier to reach than the rest. Usually, EDEKA has the best selection of those in almost everything, including drinks. Lidl and Aldi are discounters, so they mostly have their own brands. Netto depends on the location.