I went to school for Animation, and Can provide a simple high quality 2D or 3D animation (your choice, but 2D would be done quicker) using Adobe Flash or Toon-Boom depending on the requirements.
I would break this project down into a few nessary steps us professional animators use.
Step 1) would be submitting to you a story board, so you may see how the story/animation would progress.
Step 2) if the storyboard is accepted, would be to turn that into a "Pencil Test" which is sort of preliminary animation so you can see the timing, and movement of the characters.
Step 3) would be to finish and smooth the pencil test, before adding the colour tones (or lack thereof) of the animation, sure up any timing issues, round off the plot and insure the music and timing fits together perfectly.
Step 4) would be the completed animation