Quote from a Linux forum:
Every release of Ubuntu includes an updated kernel with more device support than the one before. Being a change addict I always update when new releases come out. IMHO, If you have hardware that's not directly supported by an older Ubuntu release, upgrade to the latest. WiFi support in particular continues to expand with each release.
The *.inf file is the one you need to install in ndiswrapper. Try downloading a fresh one from the manufacturer's website. SOmetimes that helps.
The *.sys file needs to be available in the same directory as the *.inf file, but it's the *.inf file you install. ndiswrapper -i /path-to-/*.inf
.....I'm a newbie and managed to get two different Broadcom cards working on 2 different laptops first time using (a) the latest release of PCLinuxOS and (b) the recommended drivers from the ndiswrapper web site. One was in fact a Dell driver.