Audio transcription for an interview.

I am looking for someone to do over 6 hours of transcription from audio interviews.
As there is so much to do, I am looking for a really good rate and very high quality so I am keen to test you on the first 20 minutes.

The interviews are always one on one. I need the transcription to identify the speaker, and add in markers for each minute.

I would like the first 20 minutes of the interview attached to be translated for less than $0.5 per minute. If the result is of the right quality then I will offer the rest of the transcription (over 360 minutes) for the same price per minute.

Please reply to this advert outlining:
1. Your experience with transcription
2. Whether you are able to identify the speaker in the transcription and add minute markers.
3. The price you can offer.

The audio file for the demo can be found on this link.

https://drive.google.com/file/d/0B-GY59oq1k7eR1duV2gtN3ZhQzA/edit?usp=sharing