For most ordinary wireless routers, 30 feet would be about tops. I am not a technician but I can tell you that wireless routers can be a pain in the neck and even something like re-adjusting the aerial slightly can boost performance. I would suggest that you get one of the long range wireless routers that retail for around £100. There is nothing wrong with your laptop.....and yes, a signal can be affected by metal objects and lights. The signal from ordinary routers is not that strong and even thin walls can affect it.