。
She played the heroine better than I did.
Literal
She [topic-は] me [than-よりも] skillfully heroine [object-を] played.
よりも is the emphatic version of plain より, with the focus particle も adding 'even more so / more than ever.' 上手に ('skillfully') is the adverbial form of the な-adjective 上手 ('skilled, good at'). 演じる ('to play, perform, act') takes its role with を (ヒロインを演じる 'play the heroine'). The loanword ヒロイン ('heroine') is the standard term in Japanese theater and entertainment for a female lead — paired with ヒーロー ('hero') for the male equivalent.