The DL answer is not really accurate because the infinitive (to use) has been substituted for the subjunctive. The literal meaning is something like: we wanted that she would have used it. But of course one would never say that in English. In real life the most appropriate translation would depend on the context since there are no perfect translations of Italian congiuntivo to English in many situations. But here without any context one has to be a bit random I guess.
sfoehner is completely right about this. The only respect in which I would differ is the implicit suggestion that the English "We wanted her to use it" is not a literal translation of "Volevamo che lei lo usasse". Certainly it is not a word-for-word translation, since translating word for word here does not result is a valid English translation of the sentence at all, but it is a literal one.
With just one caveat: depending on context, the correct literal English translation might be "We wanted her to use him".
No native English speaker would say that, though you hear foreigners say it quite often, translating word for word from their own languages. An English speaker would understand what is meant though: what is meant is what an English speaker would mean if s/he said "We wanted her to use it".
The Italian could also mean "we wanted her to use him" of course.
Joseph: It'd be the wrong past tense - 'had + a past participle' results in the past perfect tense. This is the simple past tense. or imperfect past tense. Since "wanted" in English is both a simple past tense 1-verb form, and also a past participle, it might be confusing. In Italian the forms used are distinctly different "volevamo" vs "avevamo voluto".