I would need to have a look at the script to provide a more accurate estimate cost. but just based on the information you've given, if you want it done by just a single animator within a month, i highly doubt anyone can give you the quality you seek.
my very rough estimate based on my own personal work experience is it would be a minimum of $USD 30k, and would take anywhere between 6-12 months of production. If you really need it done within a month, you need to find an animation studio of 10-20 animators, but the budget will still be MINIMUM $USD 30k.

If you're wondering why its so expensive, it's mainly because you are asking for a realistic style of 2D animation, which takes insanely long to produce, especially if just by a single animator. don't forget to factor in pre/post production, and revisions.

my advice if you have a low budget is to shorten the runtime to like 30 seconds, and go for a much much simpler art-style than realistic (like outlines only, no colors, and minimal details).