Easiest way would be to buy a DVB modulator and feed the signal into your TV system. Break into your aerial feed and loop it through the modulator, connect the HDMI from the NVR to it and then just set it up to a spare digital channel - I use 800. That will get the signal to each TV in 1080P resolution. There's a very slight delay, so on mine I have looped the HDMI through the modulator so that my main TV where I will use the mouse on the NVR is directly connected via HDMI input (no lag)
Alternatively you could use a 4 way HDMI splitter on the HDMI output of the NVR then add use CAT 5 HDMI extenders between the splitter and each TV, but you'd need to route the CAT 5's. Modulator is easiest - I use Technomate TM-RF HD IR