Unicode/String conversion questions

[Brian Pipa]

I'm not even sure this has anything to do with Unicode, but I wasn't sure what subject to use.
Can anyone tell me how this string:
Pr�t-�-Porter
can be converted to this string:
Pr��t-�-Porter
i.e. - what algorithm/encoding is being used?
Background:
I am outputting a file in a format that another program can read. When I output the first string, it chokes. When I use the native program, it outputs the 2nd string. What do I need to do in my code to output the 2nd string, given the first string?
Thanks,
Brian