Heh, Mac pro’s do not come with a wireless card, you’d need a wireless usb card…the Mac Pro is a professional grade computer, but usually for offices or “power users” who would always be plugged in so they don’t include a wifi card with them.
Something like this will do you fine https://www.google.com/products/catalog?client=safari&rls=en&q=linksys+wireless+usb+adapter&oe=UTF-8&um=1&ie=UTF-8&cid=18121627074418681699&sa=X&ei=0GOGTaCsFYXDgQfG8ZjdCA&ved=0CE0Q8wIwAw#ps-sellers
Glad to help, hit me up anytime! Hey I’m launching website & wordpress setup for online entrepreneurs in April if you know anyone!