Go the the Maps app. Make sure that a wireless network of some sort is on (GPS and My Location helps more), then you press the icon on the top right, the GPS logo. It should show you where your current location is. You will be a blue arrow inside of a circle shaded blue. Tap the arrow and it should say "My Location". Tap the text and then it will show a menu as if it were an addressed location. Tap the empty star in the top right corner and it will light up. Now you can set directions to and from the store as well as see it on the map!
Hope this helped