I don't think her conversion had anything to do with her career. It was her personal search for meaning. Orthodox Jews usually discourage conversion anyway.
Dr Laura is writing a new book. For that book she had asked listeners to send her faxes regarding what is meaningful in their lives, or how they have turned their lives around (I'm basing this upon hearing the show off and on and only hearing random comments about the faxes).
In reading these faxes, Dr Laura has noticed a great number of her listeners have been able to beat addictions, turn around emotional angst, overcome difficult childhoods,and seen the quality of their lives improved by having a personal relationship with Jesus Christ.
Dr Laura has obviously been searching for spirituality. She began with Judaism in general, and when it wasn't helping to fulfill her she dove more deeply into it, hoping to understand better the law, and probably be "better" at it, believing it was a deficit in her which kept her from feeling whatever it was she hoped to feel.
She's obviously never reached what she hoped to find. But is seeing that there may be another path to it. Maybe Dr Laura will never find what she seeks. But then, maybe she will. That she continues the journey in the face of criticism is admirable.