moosp,
Yeah, well, Wifi Extenders are a waste of time and money because of the very problem you describe. If your laptop can't get a decent signal, how is a cheap "extender" with a cheap and nasty internal or basic external antenna supposed to get a signal ? I'm not blaming you for the purhcase, it is unfortunately a prime example of the IT industry flogging nasty cheap rubbish to people who don't know their bits from their bytes.
In the business world, large premises are dealt with on a roaming basis, where you have multiple Wifi hotspots, each one of which has a cabled connection back to the main network.
I suggest you look at the same concept, because that's the only way you're going to get a decent, proven solution to your problem. Don't waste your time or money on anything else (I suppose, at a push, you could look at highly directional external antennas, but quite frankly, cables will always beat the pants off any wireless option .... and given that the directional antennas I'm thinking of need to be pointed at each other, you might as well just run a darn cable !!! ).
Yes it means running cables, but so what.... cables are the secret ingredient behind quality deployments in large premises .... the only bit that's wireless is the last leg between the final transmitter and the user's device !