convert rm to mp3

I have a sound file in rm format (Real Player). I need someone to convert it to mp3 by today. Also, you will need to give me instructions on how to do it myself next time. (free or reputed software only) The budget is limited to $10 max. Once the winner is select, -we will make the $10 escrow payment -we will sent you the sound file -you will send us the mp3 version -you will send us instructions on how to do it ourselves next time -we will finish the payment. Thanks, David