Sorry, misread on the prior thread.
I could likely get it set up if I was physically there, but DC is like 7 hours away. I find it a little harder troubleshooting vicariously.
Anyway, not sure what depth of difficulty your having yet.
Couple of different ways of approaching this. Yes I would try connecting it via a wired connection if your able to connect your mac via a wired connection.
Plug it in, and run the network config wizard under network settings > Internet connection settings > wired configuration and then walk through the rest filling in the blanks as needed.
Now if its an issue thats a little more complex like say a limitation by the school, its possible to route via your computer and have it act as a network switch and then reroute through to a wired connection. From the schools PoV it looks as if your connected to a computer, but it masks where that connection goes from there. Honestly thats a little too complex for me to try to explain, but It can be done. (downside to having my computer knowledge learned from trial and error as opposed to proper training.)
EDIT: Yeah didnt realize you were looking for a short term type solution. the latter suggestion is something that would likely take a couple hours to configure and get functional. So likely doesnt meet what your trying to accomplish.
EDIT 2: In case you would like to give that a go here is a guide to use one PC as a switch.
http://www.labnol.org/software/connect-computers-without-router/11049/
Not sure how well this would go via a PS3, but its the best thing I can suggest without having to buy something to do it, or talking with the schools IT dept to get it configured (cause I figure they prolly arent available at this hour) PS: this guide is for 2 PCs, but it should get you the rough info you need for a mac as most things like this you can do via a PC you can do via a mac in a similar way.