Until what year did the aztec calender reach and end?

Gevera Bert is absolutely correct (at least in her first two paragraphs). The Aztec calendar did not use a "long count" of years (which could specify a particular date far in the past or future) like the Maya nor as we have in the modern western calendars. The 2012 date is a MAYA "millenium" event (not an Aztec event). It is when the MAYA calendar will "roll over" to its next set of zeros (like your car rolling over to all zeros on its odometer - or how we viewed the change from 1999 to 2000).