Top Data Speed with Bluetooth on a Nokia 3650?

I am attempting to connect T-Mobile's data service to my laptop via. a
Nokia 3650 with Bluetooth. I was told that T-Mobile's data speed was
33-56k but I only get 19-21. Then I was told that BT has a upper
bandwidth limit of 19.8K so I will never get the full T-Mobile speed.
Does BT have an upper speed limit? How can I check the actual data
throughput of the connection between the computer and phone?

Thanks