Please consider hiring me for this work. I have examples of my transcription work available in my portfolio if you wish to have a look. I'm only asking for a reasonable price of $20 per hour of audio file that you have. For each hour I will need one or two working days to finish transcribing, proofreading and checking before submission.
However, I will need to ask if you would be willing to defer a little in terms of the project deadline, because it's close to Christmas right now and I'm also still in the middle of doing work for my clients. I should be completely free from 1st of January onwards. Given that this is a long-term project I presume this shouldn't be that much of a problem for you, perhaps.