You will need to get the Linux drivers for your wireless network card.
If you know the make and model, go to the manufactures web site chances are they will have pre compiled drivers and instruction on installing them.
If you don't know the make and model then you will have to open the case and examine the wireless card. There should be a silk screened make and model on the board if not then you will have to research the main chip number on the card to find the manufacture and model number.
