The licence is a one time cost, annual support and updates must be purchased if you wish to download future versions (the first 12 months support and updates are included with the licence purchase cost).
No. You get the updates for a year as part of the license. You pay the renewal fee at the end of the year for a further years support.
The 1-year extension provides access to support and updates for a year from the date of purchase. Please note that your license must be up-to-date to access certain licensed customer areas, such as ticket support.