You may have to download the windows drivers for your specific card, or maybe not there are various ways to get the drivers.
Basically
1. Some Broadcom cards are supported without you having to do anything - your card should be detected in the networking centre
2. Some cards can be supported with windows drivers using ndiswrapper to interface with the card - you can point ndiswrapper to the bcmwl(x).sys win driver copied from windows/system32/drivers (or wherever they keep 'em

) onto your PCLOS drive - The cutter applications can be used to extract the required parts of the driver from the original downloaded windows driver files.
3. Some required drivers are supplied in the "ndiswrapper - bcmwl5 and bcmwl5a" packages.
Without knowing which card variant you have I suggest that you install all the packages and then see what options you're given in PCC Network Centre>Wireless
The packages below are the ones you should be looking at to get the card working.
Try searching on Google for your specific card to see how other people have got it working, somebody somewhere will have.
If you try everything first and report back with success/errors/failures then someone cleverer than me may be inspired to help, I'll do my best

Don't give up
b43-cutter extracts drivers from .o
bcm43-fwcutter extracts drivers from .sys (windows driver file)
b43-firmware contains the necessary driver files
dkms-broadcom-wl broadcom kernel module containing proprietary driver
ndiswrapper-bcmwl5 files needed for ndiswrapper bcmwl5 card specific support
ndiswrapper-bcmwl5a files needed for ndiswrapper bcmwl5a card specific support
HTH
Kim