Hello Brad.
In my book, if it has a Econ button then it effectively has air conditioning- although I think Audi prefer to call it climate control!
I believe Econ pressed, means the air con. will not come on.
You should be able to confirm air co. by looking for the large section flexible gas pipes (with tyre type valve) leading to a compressor. Not sure how long you have had the car, but I would expect it would benefit from a re-gas every few years to ensure an adequate supply of cold air through the vents.
You are right in thinking that the air con. should automatically cut in if the temperature is set to Low, but I believe it should also cut in at any time when the outside temperature is higher than the selected inside temperature, and the control set to Auto.
Sounds like you will be need a re gass Brad. There were offers about- if you come across any good ones could you please let me know since our two cars would benefit from this too.
Kind regards,
Gareth.