。
She used the car to go to the office.
Literal
She [topic-は] office [to-に] go [for-the-purpose-of-のに] car [object-を] used.
The ~のに here is the purpose-marking pattern, NOT the more common ~のに meaning 'despite, although.' Same surface form, different grammar: as a purpose-marker it's nominalizer の + に, attached to a non-past verb to mean 'for the purpose of V-ing.' 事務所に行くのに = 'in order to go to the office.' Context picks the reading — here the predicate (used a car) makes the purpose-reading natural. The 'despite' reading would also be grammatical but contextually odd. Note the elegant Japanese economy: a single noun phrase 事務所に行くのに captures what English needs a whole infinitive clause for.