What's the process of sending back a defective N7?

[Traveler5]

Some of you know I've been having problems with the touchscreen on my N7. I don't know if it's a software or hardware issue but the touchscreen, from time to time, isn't responsive to taps and scrolls and only starts working again after a quick push of the power button. At this point I'm doing some things that may resolve it but if the problem persists and I need to send it back how do I do that? Do you get a new or refurbished back? How long does the process take?

Thanks!