Do you have a fenced in yard? How 'bout trying something like this - when you let her out... go outside with her, but before you do, take some treats out with you when you go out with her. When she goes potty, praise her lots and give her a little treat. Step inside the doorway and call for her - as soon as she gets in and the door is shut, praise her lots and give her another little treat. Love her up lots. Just remember some of this may take time like someone else said earlier - but it really is worth it. Stick with it and heap lots of love on her.
Einna