What you had was a script, not a version of mIRC. Seeing as there are thousands of scripts out there it's near impossible to tell you which one you had unless, by chance, someone happens to recognise the description as one they've used.
You can search scripting websites such as
www.mirc.net www.mircscripts.org and
www.mircscripts.com but other than that... good luck!
Regards,
