If you can't get Cat5 cable and a LAN jack installed in your situation, there is always the 'wireless hub' option. Nowadays even faster than your wired connection in most cases. They're super cheap too.
What exactly did Comcast do? That's odd they would remove something, I guess I'd have to see exactly what you're talking about. Did you have CTL DSL before? Does your cablemodem have built-in wireless, or did you have to add an external wireless access point, to connect wirelessly at your home?