Good on you and your husband for taking in this little stranger.
As Opus writes, patient, persistent kindness is the key.
Here is the link to the original post I made about Teia, the kitty that my wife and I took in 2 1/2 years ago when her previous family lost their home to foreclosure.
http://www.medhelp.org/posts/Cats/Have-adopted-older-cat--have-3-others/show/966682#post_4672404
...and here is the latest.
http://www.medhelp.org/posts/Cats/Teia-flees-the-vacuum/show/1649311#post_7515336
Teia has come such a long, long way from where she was...hurt, fearful, very timid, very withdrawn...to the picture you see with the second thread.
If you are interested, do a forum search for the key word: Teia.
Gods Bless and Merry Christmas!