Either bring it to a Nokia Care Center (repair by 6pm on same day) Or if you are in a outskirt town, drop it off at the dealer where u bought it from, you should get it back within 3 days.

FYI. AGPS uses network to log on to a Nokia server somewhere. From your phone number it can tell which country you are in, so it will only lock on to the relevant satellites (there are altogether 27 satellites for GPS in space). To know your position, it only needs to lock on to 3. Most of the time the phone can lock on to at least 5. Future versions of AGPS will be cellular network based. It can detect your position from the network base station.

Also if you can't update firmware by flashing yourself, just take it to a Nokia Care Center for flashing. Lots of goodies with new firmware. On top of AGPS, you have faster camera function, more RAM freed, and presumably better battery life (now, I know a ton of users who will appreciate this). But I am not sure by how much more.