。
She's an actress rather than a singer.
Literal
She [topic-は] singer [rather-than-というよりは] actress is.
A close cousin of the X というより Y construction: adding は after より gives a slightly contrastive emphasis ('as opposed to calling her X, she's Y'). 女優 is the gendered noun for an actress; modern Japanese is gradually moving toward gender-neutral 俳優 for both men and women, though 女優 remains common. The closing である is the formal/written copula, giving the sentence the slightly polished register of biographical or critical writing.