Currently Being ModeratedSep 16, 2013 9:23 PM (in response to guidodp)
Well, the only solution would be if you had been syncing the contacts to a supported application on the computer or to iCloud. You can update the 3GS to iOS 6.1.3, but you could not use the backup from the iPhone 5, since it was probably on iOS 6.1.4. The sync is your only solution.
Currently Being ModeratedSep 16, 2013 9:24 PM (in response to guidodp)
Your contacts should be on your computer in whatever program you have been syncing. Just sync them to the new phone