I suggest you get good with the network admin
But seriously, theres probably nothing you can do other then cutting back on your downloads. Or if you are roomed with someone unkown in the computer ways, get a router and use up one of your lines then switch to the other.
About the 3gb in 3 days. Here in Nova Scotia I have heard of people getting there service pulled for doing stuff like that, cuz the college mostly thinks your either a MP3 server or worse.
I can relate with the massive storage amounts I averaged 50+gb down / 30+gb up for 2 months in a row and my DSL service sent me a nasty e-mail saying that it was strike one (get to strike 3 and I get my service either cut / capped) which I think is VERY stupid, saying its uncapped then getting pissed when I use up too much.....
Anyway, I would do what most people up here who need the bandwidth do, move into a apt with some friends and split on a Unlimited DSL / Cable service.