Wi-Fi signa becomes very weak when more than 10 metres away from router...

Hi,

I live in the UK and I used to have standard 8 megabyte broadband with no Wi-Fi signal issues at all. I have since upgraded to 38 megabyte Fibre Optic broadband with a different ISP and with a different router and I keep having signal issues.

My router is a TP LINK TL-WR841N 300Mbps Wireless N Cable Router 4 Port Switch. It has two antennas so I thought it would have a very strong signal. Wnen I am very close to the router, for example, no further than 2 metres away, the speed is great. Also when I have the ethernet cable connected the speed is fine. However, when I go upstairs and I am about 10 to 15 metres away from the router, the wi-fi signal becomes very poor and I can't stream videos properly or browse web pages. Some times its ok but it comes and goes and is unusable most of the time.

I wanted to know whether this is normal for a router, or could it be a fault? Is it worth returning the router for a refund, or should I buy one of these wi-fi signal strengtheners? Also, do you know if this router can allow me to receive full speeds from my 38 mbps connection?

Many thanks for your help in advance,