Correct me if I'm wrong, but I do not think we can put a (R) or a (TM) on it, unless we have specific rights to do that. We are not the trademark owner, nor have permission. (I don't think what you're thinking of doing with these cards would warrant a trademark).
We don't use one
http://www.1addicts.com/ on the main page either, and that card has an identical intent. If we used the roundel, that would be a different story...