。
She's facing the other way.
Literal
She [topic-は] other-side [object-を] is-facing.
向こうを向く ('to face the other way, to turn one's back') is the set phrase. 向こう ('over there, the other side, beyond') has both literal and figurative uses; in this idiom it marks 'the opposite direction.' を + 向く is one of those を-with-direction-verbs constructions: not a true object, but the direction faced. The resulting-state ~ている describes her current orientation — back turned, gazing the other way.