Plugin wanted to save emails as .rtf files and automatically rename them

I've just changed from a PC to a MAC. On the PC I had a plug in for Microsoft Outlook called Message Save by Techhit for saving emails
http://www.techhit.com/messagesave/

It allowed me to quickly save emails to any folder on my hard drive as a .txt file and it automatically created a name with the date, to, from and subject fields.

Is there anything similar for Apple Mail? Doing File > Save As and renaming them myself is too slow.

Thanks
LeahyJ