Connection Issue

I have not been able to move my internet to my LR so I can patch cable the Roamio OTA into the router since my wireless is too weak to stream video upstairs in BDRM with Mini...Pandora is fine. I have 1 coax line (MoCA) in the LR but when I hooked up router and Tivo with a diplexer I got a blocked signal on both. Separately they work fine, I just need a hub or something to split my OTA/Internet signals.. Any ideas? Otherwise everything is great.

BTW thanks to all the good people for answering so many questions..