。
She's more of a singer than an actress.
Literal
She [topic-は] actress [rather than-というよりは] rather singer is.
というよりはむしろ is the emphatic form of というより (rather than), with は adding contrastive emphasis and むしろ (rather/more precisely) reinforcing the correction. The full pattern recharacterizes her identity — she may be known as an actress, but the speaker considers her fundamentally a singer. This structure is useful for politely correcting characterizations or making finer distinctions about someone or something.