With that many wireless channels being used in your area it's not going to get much bandwidth, plus you have a very weak signal to begin with, not to mention your stuck at 54mbps speed which is very old school, I'd say this connection won't be too great no matter which channel you use. Although channel 8 looks to be ok for now.
In your scenario I'd replace the router or obtain a wireless access point that can handle wireless N and also has the newer 5.0Ghz frequency because it has the potential for much more bandwidth and clear channels that aren't already being used by fifty people.
I would also either move the router to a more ideal location for a better connection or install an access point very close to where you need to connect from. Setting up a wireless router or access point with the 5.0Ghz frequency and setting it to use wireless N only
in close proximity to your computer would be ideal here.