There are a number of solutions available to you, each varying in the technical prowess needed.
One way to extend the range is to use a wireless repeater, something like this product on Amazon. This has been tested by users and has been found to be an effective solution in their circumstances.
Now, it is extremely important that you use a universal repeater, even if you don’t go for the product I have linked. Normal repeaters will definitely not work on later models of the BT home hub. Don’t buy a repeater unless it is universal.
Another solution that some users have had success with is to use your mains power to take the Ethernet signal from one of the ports on the router to another point somewhere else in your house. Next, you connect your computer to the Ethernet port on the second power line adapter.
Neither of these are 100% fool proof, but neither are very expensive either. If you’re having problems with the range of your router then give them a try, I would love to know how they work for you. If you have any solutions of your own that solved the problem then drop me a line and I will edit this post to include them.