30 foot is the range.
Bluetooth range is roughly speaking 100 mts. This ofcourse means uninterrupted 100 mts distance. As you decision to send files through floors, i sincerely doubt if it would work through three floors. Doors, Walls etc create barrier and prevent the phone from detecting other users with bluetooth access on.. This have nothing to do beside the specific Nokia 6300. All bluetooth phones will have these consraints.
You can other try to send the files 3 floors above by standing fundamental a staircase and preferably the recepient is also near the staircase.