I think its a matter of being a little more complete with your post (the original one). Something more like, "I have this metal building, and it has C channel girts and purlins in it that are x by x inches and x gauge steel (the gauge should all be imprinted on the existing steel) and I need to replace a couple of sections due to (damage, rust, modifications, etc) and I'm having trouble locating a supplier of components for steel buildings."
http://www.allsteel-buildings.com/
10159 Us Highway 41 S, Gibsonton, FL 33534
(813) 671-8044
www.metalbuildingoutlet.com/florida.html
METAL BUILDING SUPPLIES, LLC
(407) 935-9714
800 E Donegan Ave, Kissimmee, FL 34744
Any metal building manufacturer can tell you who to contact to find what you need.
Charles