welcome to WebmasterWorld, jennypretty!
it depends on if and how you can identify and define the pattern of the old urls translating to the new urls.
- all the old urls to be changed start with /dating/
- all the new urls start with /free-dating/
- all the old urls to be changed end with country_name_singles/
- all the new urls end with country_name/
then the answer is yes, you can do this with a single mod_rewrite directive using RewriteRule using capture groups in the pattern and backreferences in the substitution string.
if there's more going on than i assumed above then you will have to provide a comprehensive problem description.