That is because it has an internal wireless card which is only rated at 54mbps.
Do you do a lot of large file transfers across your network of do you do a lot of latest game playing across the network? if not 54mbps far outstrips any BB connection speed availiable at the moment.
But if you still want to speed it up then you will need a wireless adapter with the faster speed. click here There are a couple of 108mbps USB ones on this page.
click here There is one 108 mbps PCMCIA card on this page.