You shouldn't have a problem adding your router back to the network,even if it's on top of comcasts proprietary shit. Verizon does a similar thing with a 4 port wifi ready modem that I can't stand. I just add my router on top of it. Personally, I'd recommend you hardwire any internet ready device you use. Before you say things like "too far" "diferrent floor" etc etc, I do it for a living and it's not as hard as you make it sound. Tablets, phones and other obvious wifi onry shit yeah, you're limited to wifi, but anything else hardwired is best.