802.11B is 11Mbps.. 802.11A is 22Mb.. anyway, I digress.
What speed does the wireless connection claim to be running at? It is possible to force this to 1Mb on some adapters.
Go to Start, Settings, Network Connections and select your wireless connection. Properties, ensure 'Show icon in notification area when connected' is ticked (this will tell you how fast the connection is by means of a little blue/black flashing icon at the bottom right). Click Configure next to the wireless card and under the advanced tab there should be a setting do with speed / duplex.