walmart gps locations
Garmin GPS question about where to locations.?

i have the garmin street pilot c330. the only complaint i have is the fact that there are some stores in my city that are not located in the where to searches. some examples include a grocery store that has been open for atleast seven years, our walmart that has been open atleast four years, my school that has been open for atleast six years. i was curious as to whether these locations come preloaded on the gps or if it retrieves this information from the satellites each time. like say a business changed its location, would it eventually update or would i manually have to purchase a map pack with this updated info on it? thanks in advance

I just bought a c330 too. You’ve got me a little worried, I hope I don’t have that problem.