Very-very long-range wifi modem

[ashish]

being using the D-Link repeater for a month and the signal quality is awesome. 100 % range where previously it reached 15-20 %

 

[fiberguy]

I bought a D-Link N300 2750U. It works fine and has a good amount of range. It also has a USB port which is useful!

 

[kumarlabels]

Cisco provides good wifi modems

 

[mega_processor]

A high power modem would cost around 8k which is less than a low power wifi modem+repeater
typically wifi modems have EIRP(radiation power) of 100mW.for your case a 2W would be more than sufficient.Belkin and Cisco have those models.
repeaters available are 10mW and hence they cannot be a much help in a case where the rooms of usage are placed randomly.