Hey FurryNutz,
Thanks for the response!
Since posting, I've made a bit of progress. Basically, the IPv6 connection is up and it useable, but the router is not pushing itself as the gateway. It assigns IPs to the computers, but unless I manually add the gateway address, it's a no go. Not sure what I'm missing now.
To answer your questions, my provider is Teksavvy DSL (Canada). The modem is the one I'm forced to pay rent on which is the CellPipe 7130 (I believe it's an Alcatel Lucent).
I did try bypassing the 655, but I'm not familiar enough with IPv6 to get my laptop working on its own. OS X seems to be a little bit picky in that way.
On a side note, the router is not advertising the gateway on OS X, Linux, or Windows 7 machines on my network. Previously I had been using TunnelBroker's 6in4 on a 615 and that was able to push the gateway just fine.