When you installed the mods in Windows, they must have been downloaded to some folder or other. There should be a folder called "mods" somewhere. It might be somewhere inside \Documents and Settings\[User]\My Games\ or it might be in \Programs\Civilization 5\ or something like that. I bet you can google the location pretty quickly.
They should exist in two forms: a compressed file with an extension like .civ5mod, and as a folder. Inside each mod's folder you'll see a file with an extension like .modinfo along with some subfolders and/or some .xml files, that kind of stuff. You want the mods' folders.
Once your Mac is set up (btw it's "Mac," not "MAC") and Civ5 is installed (I assume you're doing it through Steam... should be free that way), go to /Users/[user]/Documents/Aspyr/Civilization 5/. Look for a folder called MODS, if there isn't one then create it. Dump the mod folders there. And please refer to the sticky thread I mentioned above to make sure I didn't get that directory wrong.
When I first switched to a Mac, the OS was only on 10.3 or so, I remember it felt kind of amateurish and toy-like at first. As the OS advanced and I learned more about how it works and about it's UNIX underpinnings I came to really respect it, I think it's the best OS out there to work with. Give it a couple weeks, get used to using CMD-c instead of CTRL-c, and you'll be fine. Especially with that hardware - great keyboard, great trackpad, great screen. That stuff really helps interacting with a computer be more pleasant. Enjoy.