Dont know if your kernel has inbuilt support for your card - type lsmod in console and see if bcm43xx appears. If it does then try, as root, modprobe -r bcm43xx, modprobe bcm43xx and check dmesg for any errors. Could be looking for firmware. Another point is the 4318 chipset is not well supported yet so it may not work at all even with firmware, see this http://bcm43xx.berlios.de/
. Another option is ndiswrapper
which is included on Mandriva installation disks so no problem installing it.