Interpreter for I-485 Interview

[BlackSteed]

I am scheduled for my green card interview at the end of this month. My wife and I are native Spanish speakers. My wife is already an American citizen and also my petitioner; she speaks English very very little; whereas I am fluent. Will I be allowed to translate for my wife or should I bring an interpreter?

Also, I submitted an affidavit of support together with my I-485 application, 8 months ago, do I need to update the documents related to the affidavit: ie. paystubs, tax reports, etc?

Thanks for your help in advance. This forum has been very helpful to me.