[X4U] blue tooth

[Robert]

Stupid question, but when I got my dual 2 it came with an external blue 
tooth antenna. If I go to system profiler it does not show blue tooth 
in my computer. Does this mean that blue tooth is not in my computer? 
If I this is the case what is the point of having the antenna? Is there 
a blue tooth adapter from Apple or from other parties that can go 
inside my Mac? If I have to purchase an adapter does any one have that 
they recommend. TIA  Bob