Translation:She had not given an interview in a long time.
I believe "she hasn't given" would be "ela não tem dado" or "ela não da", because the condition of not having given still holds "Ela não dava" refers that the condition held sometime in the past, but says nothing about it now, so my opinion is that the correct translation of it is "She had not given". Maybe she already gave one this morning.
The English translation is in the past perfect tense. The equivalent tense in formal Portuguese grammar is the mais-que-perfeito tense. Both tenses correlate perfectly.
• Ela não tinha dado entrevista há muito tempo.
• She hadn't given an interview in a long time.
The "mais-que-perfeito" tense has fallen into disuse in spoken BrP. Instead, Brazilians use the imperfect (dava) which can't be translated to English in a way that would make sense.