If your tablet died BEFORE the warranty expired, they are legally obligated to repair or replace (at their option), provided you have not otherwise voided the warranty (read the fine print).
If it died after the warranty, you're SOL, but that's not Asus's fault. You would find the same situation with any manufacturer.
Your experience is unfortunate, but also unfortunately universal. Just check any auto enthusiast forum, where people talk about some major issue cropping up soon after the warranty expires.
you can, at least, replace it with a new or refurbished 2012 N7 pretty cheap. check ebay, google... warranties end when then end, not much anyone can do...