I dislike going to the dispensaries. Having said that and without giving you my last 5 years of life's turbulent BS, I find them easily accessible and in exchange for quasi legal meds I have to pay a premium...Therefore, I've been med free (not by choice) while I continually invest in equipment...
I too have a Mac and had trouble while using Adium. (http://adium.im/)
I installed Colloquy and haven't had any problems since. (http://colloquy.info/)
Hope this helps!