Can anyone direct me to software that can be purchased to use with muds, for macs?  Something that can be purchased in store I’d prefer, but if it needs to be purchased on line that will work.....

Gee, I don’t know of anything like that. I’m on a Mac and I just use Atlantis:
http://www.riverdark.net/atlantis/

It’s good - I like it quite a bit.