I have had Virgin broadband (updated) for many years with the router being situated in my front bedroom where my old computer was. I now have a laptop as does my wife and we tend to use these in our lounge which is at the back of the house with a couple of walls in between. Depending on where I sit I keep losing my connection. I could live with this but I have now started using my Samsung smart TV to view photos and videos from my laptop on my TV but the loss of connection from my WiFi router means I cannot view much. It is really frustrating and makes me wonder why I pay so much money to Virgin if they cannot connect me throughout the house. Is a WiFi booster the only solution or having my router relocated.
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Something on the lines of this would probably help you. It using the house wiring to transmit the broadband signal from router to a wifi transmitter plugged in to a socket in where you want to use the signal.
I'm not recommending this particular product. I have never used it, but just giving it as an example of what is available to resolve your problem. There are several other products on the market which do the same thing.
I sympathise with your problems. Nothing is getting any cheaper nowadays. However, in fairness to Virginmedia, your enemy is the law of physics which governs the propagation of radio waves. You probably live in a "proper" house with decent walls rather than the flimsy things in modern construction. You may find that using the 2.4Ghz wifi is better than the 5Ghz as the absorption is greater at higher frequencies. I wish you well.