I have a factory GPS nav unit in my 2008 Audi A6. However, it appears the search capability of the unit is limited. For example, there is no category to search for just shopping. There is a shopping center category which gives you malls, strip shopping centers, etc, but not a shopping category that allows you to search for shopping and a specific store. Is this a limitation of the hardware or do I have old mapping software? If the mapping software is old, where can I purchase updated software cheaper than at the Navteq store?