Welcome back Darkfader!

Unfortunately, there has not been and it does not see like there will be official news of an upcoming expansion anytime soon. STS has been focusing much of their work in Arcane Legends, which was released in early fall last year. It has been there biggest hit yet which is why all their other games haven't been getting as much attention.

Regarding your second question about the three elite set rewards, no, this is not the last chance to get the ring. In case you don't know, those with 2 elite vanities can receive a two piece elite vanity ring. Those with 3 or more can receive a different ring. The stats that these rings grant are the same as you would get when you used to get in the past when you would wear 2 or 3 elite vanities. You will still be able to receive these rings in future elite caps. You can receive yor ring(s) from an npc in blacksmoke mountain town. I don't remember his name but stands by a dragon in a cage.

Once again welcome back and hopefully this answers your question.