There is sadly enough no new Avatar series that will be made, at least not in a long time, but if you are interested in the Avatar comics or other Avatar merchandise, then I recommend you to take a look at this blog post http://avatar.wikia.com/wiki/User_blog:Water_Spout/Looking_for_what%27s_new_in_the_Avatar_scene%3F_Here%27s_an_upcoming_merchandise_and_publication_masterlist!.
Right now, there has been no announcement that there will definitely be another series, but they also haven't said they will never make another one. If they do make another series, I would expect it to be a few years at least.
Why would I be angry? Your question is something every Avatar fan wants an answer to if they don't know it already.
Nevertheless, I also want them to make a new series, but I understand that it takes time to make such a good series as Avatar, so I rather see that they take their time and make an eventual new series as good as the previous ones instead of rushing it and risking that the new series might end up being 10 times better than the "The Last Airbender" movie (which would be horrible).
By the way, welcome to the Avatar wiki!