If you can get to the command line and into the directory where your .CRD files are located ...
1) do a quick test ... select a file (for example, FRED.CRD)
2) type: REN FRED.CRD FRED.RTF
3) check the file to be sure it has the ".RTF" extension
4) if that worked, type
REN *.CRD *.RTF
to rename all the .CRD files in the directory. Then you can copy them, and, when you're finished copying, type
REN *.RTF *.CRD
to put all the files back to their original name.
Fred