You can buy these products,but you could also rig one your self with an old antenna and some coaxial cable.
you can buy range extender antennas that clamp on to the existing base station antenna
Cordless
The Panasonic DECT 6.0 Digital 5-Handset Cordless Phone is great.
Siemens Bigaset SL785 is a good choice when looking for a good cordless phone. It offers 1.9 GHz, expandable up to 6 handsets, wall mountable, and ultra slim design!
the top three best cordless phone for any needs that you need is always Samsung gigaset. It has numerous appreciation and good reviews for all you need
A cordless phone?
the Vtech DECT 6.0 Expandable Three Handset Cordless Phone System is a good one.
I believe reading reviews written by other consumers to be an excellent source in finding the best product for each need. One very good site which has cordless phone reviews is: http://cordless-phones-review.toptenreviews.com/ , consumerreports.org is also a good place to read reviews so you can make an educated decision.
You can purchase a cordless phone battery at Best Buy, Amazon.com, ebay.com, www.batteries4less.com/contents/Static/cordless-phone-batteries.html, etc. There are many options.
To find the best cordless phones out there I suggest you look on amazon.com, they have a good rating system on there so you can look at reviews and prices.
There are many places where one could find good deals on Big Button cordless phone. One could try online shops such as Amazon or eBay for deals on this product.
A cordless phone twin is set up by , plugging the base into the wall and the phone jack , one then can plug in the cordless phone twin into any outlet and ones phones will be set up.