Audio Conpression tool

I require an 'easy to use' audio compression tool. The user can drop an audio file onto the *.exe, the program will convert the audio format to Mp3. The program will attemt to compress the audio to within a selected predetermined file size range,like 50, 60, or 70Kb etc. If the compression is below a certain quality, a warning notice will show asking the user what to do next, shorten length, or continue. The audio range is between 12 ans 20 seconds, so we are not working with big files. A simple GUI, graphics will be provided.