If you wouldn't mind, I'd love to find out who all are you colocating with & how many rack units and amps your using. Usually when I price out colocation it comes out to be much more expensive than just leasing a server.
I use a data center in Oak Tower. There are several data centers in the tower. The one I use is Joe's Data Center (Creative Name Eh?) I'm only renting a 4U slot (My server is a 1U) and is $49 a month for 1.5 TB Bandwidth on a Gigabit port.
I assume you mean 1 Gigabit/Second of Bandwidth and 1.5TB of transfer usage.