A "Repeater" or "Range Extender" is the device that extends the range of a wireless network by rebroadcasting the signals it receives. I doubt that the Westell model A90-750015-07 modem/router has this feature. Login to one and look around the configuration pages (or the specs or a manual) to see if it does.
You can use any router or modem/router as a Wireless Access Point. Can you place it somewhere more convenient to the space you want to reach, maybe in a window, and run an ethernet cable between it and your router?
You can use any router or modem/router as a Wireless Access Point. Can you place it somewhere more convenient to the space you want to reach, maybe in a window, and run an ethernet cable between it and your router?