How limited is the range? Vertical or horizontal?
We have a lousy setup. 2200 sq. feet. mostly on one level.
The lousy part is that the whole modem/router setup is at one end of the house.
Decent coverage extends to about 60% of the house. I guess if the main system was centered in the house we wouldn't have many issues upstairs or down.
There is also an option of a USB receiver. A couple of our laptops don't have decent hardware but when I plug in a new USB receiver and disable the on-board receiver I get better reception.
That option is not available for the smart phone though.