Have you updated your roaming list since moving? If this is your new "home" area, do a *228 option 2 to have your phone reprogram and locate your new towers.
If it is still saying "extended area" after the update, check with the local store or *611 to make sure there is no issue with the towers near you.
Some areas are still going under conversion in which people will see "extended" for a period of a few weeks (exact time unknown at this point).