How to best Expand RF Range

[JW <JW>]

I have a dozen modules around the house controlling lights...all on
the same phase, so I'm in no hurry to install a phase coupler.

What I would like is to expand the RF range within the house, and
outside, as well.

I have the CM15A centrally located, and it works great as long as I'm
within 20 - 25 feet, but beyond that, forget it.

What is the best way to extend the range?  I have two floors +
basement, and the house is about 75' from end to end.

By the way, this is a great forum and the information provided here is
much appreciated by newbies like myself.

Regards,
Joe