。
She makes her living playing the violin.
Literal
She [topic-は] violin [object-を] play-and living-expenses [object-を] is-earning.
The te-form 弾いて here functions as 'by means of': linking an instrumental action to the main verb. Where English uses 'by' or 'through,' Japanese often just chains a te-form. 生活費 ('living expenses') paired with 稼ぐ ('to earn') gives the standard idiom for earning one's living, with ~ている marking it as her current ongoing situation rather than a one-off event. A more compact alternative would be 生計を立てる, a slightly more formal set phrase for 'to make a living.'