Would love to join a group to share thoughts and ideas.
Me too.
I've looked into this before. There is not specifically an arduino or robotics group in Austin. If you get to Dallas once in a while you can drop in on the friendly DPRG.
For Austin, there are some related groups. Dorkbot
http://dorkbot.org/dorkbotaustin/ is a "techno-arts" group, more arts than technical. They do some things with arduino.
You might also find some like-minded people at the ATX hackerspace
http://atxhackerspace.org/wiki/Main_Page. They have a "microcontroller mondays" meeting which might include some arduino people.
I haven't had much of a chance lately to get to any of these meetings myself. Let me know how it goes.