You can get the full, final standard directly from the ISO, or some national bodies.
You probably don't want to get in a hurry though. The ANSI (for one) normally re-publishes an official version with identical technical material -- basically the only change is saying "ANSI/ISO" on the the title page instead of just "ISO". At least for past versions, however, the price has been much more reasonable (~$30US instead of ~$400US).
Edit: As expected, the standard is now available for $30US.