replaced iphone apps not transfered

I had to recently replace my wife's iphone 4...battery issues, with another iphone 4.  I followed the directions given by the phone company...backed-up the phone on itunes, synched the new phone to itunes.etc.  But, when I checked the new phone to verify that all of her previous data had tranfered I noticed that none of her apps had.

So, I went back and looked on itunes and it shows that she has never purchased any apps....which I know is incorrect.  How do I restore the apps that she purchased through itunes?

Thanks