there is an output strength option in the routers UI 192.168.1.1:8080 (default). you can adjust it from 0-200 mW. where available =).
antennas usually work best \!/ <=== @ this configuration. I hope that helps ya.
I also know that 5ghz signal can be easily interfered (my tv looses a bar of signal when someone walks in front of the tv) It "usually" provides you better bandwith than 2.4 even when 5 has a lesser signal. If this does not help you then I suggest drop kicking your Apple products into a urinal (one without a cake) then go get yourself a Tf-700 aka. Transformer Prime Infinity with a dock.
oh, um. yeah, ya know what? you should just go ahead and do that. yeah... now drop. kick! =)~