alt.internet.wireless

At work our internet via network cable is slow and keeps dropping out,
due to the proxy server, etc. However we have internet by wifi. Is
it possible to use the wifi on my notebook to access the internet and
the ethernet port (cable) to access the local network? I'm using
Windows Vista, but if someone knows how to do it with XP I can figure
it out. I search but haven't found anything for what seems to be to
be a simple request.

PS: If I activate my wifi and have the LAN at the same time, I can't
seem to access the internet. Not sure why..

Thanks