Replace faces in a video clip with provided pictures ~$40/min

I need someone who can take some video clips (from the Avengers movie) and replace the faces and other objects with pictures I provide. I can actually do this myself using Adobe Premiere, but want a better looking production - one in which the superimposed faces and lips move exactly with the video. If you do a good job, there are a few other video clips I would like you to work on as well. I am willing to pay approx $40 for each minute of video. There will likely be around 5 minutes of video to be edited in total. Deadline would be around 1 week although it is somewhat flexible. If you can send me a sample of similar work you have done, that will be very helpful (but not necessary).