Hi, your issue is not unique, many people have this issue, besides just wep encryption there are some routers that do not do well with linux.

Since you are only having problems with one location and you are not having any other issues then I doubt that reinstalling ubuntu will help.

You could find an updated driver and try it but this has been going on for a long time so again I do not think that will help but you could try ndiwrapper it is best to ask for help installing it here:
http://ubuntuforums.org/showthread.php?t=885847
Thanks