Wi-Fi signals are very fickle and reception can be affected by numerous things including distance from the hub, how many walls are in the way and how they are constructed, interference from neighbour's Wi-Fi signals and domestic appliances that emit rf ... the list goes on. It doesn't help that the hub's design has the aerials inside the casing ... if you look at any decent router design it has external aerials.
You could try experimenting with the position of the hub if there's any scope to move it about. You could try changing the Wi-Fi channel to see if that avoids interference (see video tutorial at top of this page). Stick with either channel 1, 6 or 11.
Failing that you are left with having to spend some money, either on Powerline Adaptors which use your mains wiring to carry the signal to another part of the house or putting the hub into Modem Mode and buying a third party router such as an Asus that will have a better Wi-Fi signal.