Use of external lap top microphone

by Sal
(Turkey)

I have a vocal cord problem and I cannot speak in high tones. I would like to use and external or computer's own internal mic to boost my sound when I am speaking with the computer and mic. in front of me. I bought a Hama condenser external mic., I can use it to record my voice but I cannot use it to drive the computer's speakers directly. Do I need a software to do it or is there any adjustment I have to do?
My Lap top is Toshiba and I am using Window Vista.
Thanks in advance.
Sal