Boost wireless signal

[R.R.Mac]

I have a Black Macbook at the moment and I have heard rumours that you can buy pieces of USB hardware which will boost my wireless signal range.

What I mean is that I have a very low signal in my room and I would like to be able to get a stronger wireless signal, however my airport card isn't good enough so is there a USB stick or something that I could plug into my computer which would give me a better signal.

Links would be appreciated!!

Thanks,
R.R.Mac.