Linda,
I think what you may be looking for is a Wireless Signal Booster Antenna. I have never had one, nor do I pretend to know anything about them.
However, we had an RV (which we recently sold after buying in TV) and I remembered reading about them on one of the RV forums. Looking at one of the forums today, I see that one place comes highly recommended for this type of thing. The site is:
http://3gstore.com/index.php?main_page=index
Now, this is all Greek to me, but maybe if you call them and explain what you're looking for they can help.
Hope this helps to put you on the right path and not some wild goose chase.
Wishing you many more Skype calls with that wonderful son of yours!
Dianne