I was in a similar predicament in my last house. I found a really good solution in the homeplug adapter.
I dont want to sound condascending and just to explain, one homeplug adaptor is used to power the router, the other homeplug is inserted into any power socket in the house. From that socket you can then use an ethernet cable to provide you with connection to the network.
These things come in at around 70 quid for the pair and offer up to 300 MBPS connection speed and for me the best solution going for you. You can find these things online as well as in the shops. These are also known as powerline adaptors.