Complex sentence: In 2000, when Melanie Thornton left the group to start her solo career, Frank Farian brought Natascha Wright to "La Bouche", to be the new front-woman and the group recorded a new version of the song with Natascha's vocals.
Split into simpler sentences: In 2000, when Melanie Thornton left the group to start her solo career, Frank Farian brought Natascha Wright to "La Bouche" and she became the new front-woman of the group. That same year "La Bouche" recorded a new version of the song with Natascha's vocals.