TMOG4AR Gateway

I'd really prefer getting it delivered as I would then have time to test it to make sure it works before returning the one I'm currently using. The Arcadian gateway I'm currently using only works in one spot in my house which is about as far away from my tv, etc, as possible causing weaker Wi-Fi. I'm hoping to be able to place it near a different window closer to where everything else is. My understanding is that I will be able to easily add an external antenna with the new gateway, if needed. I tried adding an additional router but have found that to interfere with the Wi-Fi coming from the gateway, giving me slower speeds, even with them separated by about 3 feet which I believe is recommended.