hi
the range of any access point depends on a few factors when in a building - area / wall or ceiling blocking / signal interference.
Rather than use specs and statistics, your best bet is to turn on just one of them and get a laptop and go all around the area you wish to cover and see how the signal holds up. Then boot another in an overlapping area thats not receiving coverage etc. Places that will cause interference with signal are powerful lighting, elevators, refridgeration units, comms room power etc
These areas can be difficult to cover.
cisco do wireless lan controllers for multiple access points but realistically thats not what you need here. A WLAN controller is a unit for managing several LWAPs (lightweight access points) - these sit on the LAN and are centrally managed from the controller - controllers are quite expensive and are aimed at Campus environments.
Your environment sounds like it just needs better coverage so you can add devices accordingly to ensure better signal. There are devices like repeaters and signal boosters but considering the now lower cost of APs, it makes just as much sense to put in an access point where one is needed.
