The folder should be in something like C:\Program Files\Quake III Arena\westernq3
Then you use a program like
http://www.winzip.com (trial version is good enough) to unpack the fan_maps.zip to that location. If you're using windows XP you don't need winzip. Just double click the file after you download it & extract to the westernq3 folder I mentioned. Since you have a roomate, I'm guessing you're in school? Get a more knowledgeable friend to help if need be. Sorry you're having trouble, but there's only so much more we can do here. Hopefully, the standalone wq3 will be foolproof once it's released. In other words, everything will install by itself & nobody will have to go through such troubles.