I have an old, rambling farmhouse, with thick walls, subsequently covered with vapourshield plasterboard, so the range within the house is poor (although I can pick up my neighbours WiFi quite happily!)
I have tried quite a few things, and decided that cable is the best way to go - more secure too.
I too tried the repeater method and it made no difference - the repeaters I came across are of two types, one that retransmits on the same channel, so you can wander about the house with your laptop without having to retune, and the type that picks up the original router signal and retransmits on another channel, so there is no chance of interference - but no good if you want to use your laptop on the hoof.
However, I then picked up a BT Broadband router (for free from Freecycle - still shrinkwrapped). I'd heard that they had a better range than normal. I had to flash the router to make it work from my obscure ISP (the BT one will ONLY work with BT unless it is flashed - an easy job). I can now get good signal throughout most the house and an acceptable singal in the "fringe" areas - e.g. at the end of my kitchen. It is worth trying different postions for your router too. I wanted to have mine in the Study, and have my printer cabled in to it, to make the printer wireless from the laptop. I couldn't get the range though, and it is now in a spare bedroom about 2 feet away from where I wanted to use it, but it's 2 feet of solid wall!