I'm not sure that you would need a new wireless card. It may just be a matter of configuring your existing card. Once you get it working is should remain working. Can you provide details of the exact brand(belkin), model, and revision? This should help us all to determine it's compatibility with linux, in general.
Regarding samba password message: Please explain what process you are using to attempt accessing the XP shared folder from Vector Light. What software are you using to navigate to the XP machine? I recently wrote a how-to on creating a static 'Network Neighborhood' for VectorLinux that makes the workgroup easily accessible (http://forum.vectorlinux.com/index.php?topic=10471.0
). If the Vector Light machine only needs to access the XP machine (and not vice-versa) then you should only need Section 1 of the how-to.
Hope some of this helps.