You have several options to boost the signal. Below are the details and differences among each of these solutions:
Roqos Core works with any Access Point, like Google OnHub, Apple Airport Express, or any other router that supports Access Point (AP) or Bridge mode. With access points, you have to connect the AP to the Roqos Core via an Ethernet cable, and the AP broadcasts a wireless signal. This is the easiest and best option in terms of bandwidth, if your house already has Ethernet/network cables between floors, otherwise you will have to run a long network cable to the Access Point.
Roqos Core also works with Mesh Wireless products as long as they are in bridge (or access point) mode, such as Plume WiFi, Netgear Orbi, Luma, Eero, etc. With this solution, you connect one of the Mesh devices to Roqos Core with an Ethernet cable, and the remaining units connects to it wirelessly. If your house does not have built in Ethernet cabling inside the walls, this might be your best option. Make sure that the Mesh device can run on bridge mode. If bridge mode is not supported like in case of Google Wifi, Roqos Core functions are still available but device level granularity needed for filtering will be lost.
Another alternative, if there is one single computer you need to connect, would be a Powerline Ethernet solution. Powerline Ethernet uses your house's electrical wiring to carry network signals, so you would connect one unit to a nearby power outlet with Roqos Core, run a network cable from that to Roqos Core, and plug the other one into an outlet close to your PC upstairs. This solution depends on your house's electrical wiring though, old houses have either poor quality/degraded wires or a lot of electrical interference from certain things on the line, such as sump pumps, window type AC units, etc. This solution would be the most economical though.
WiFi extenders are the last alternative. However, some WiFi extenders due to their operation disrupts Roqos Core's ability to identify devices. Technically, WiFi extenders change the MAC address (think of it as the serial number of your devices) of the devices connected to them, making it harder, and sometimes impossible for us to identify devices connected through them. This affects our filtering abilities as we cannot distinguish devices between each other. Access Points and Mesh Wireless systems mentioned above do not have this problem. Currently we can only recommend TP-LINK RE200 and RE650 models of WiFi extenders.