You have two choices here: either do it yourself and save tons of money or trust a "mechanic" and let him take your money.
Good mechanic is a hit or miss.
The main reason I started working on my cars myself is the way I have been treated by so called "mechanics"
So, if you decide to do the work yourself, let us know and you will be guided.
If you decide to take your car to a garage for them to do the work, try to go to a different one and see what they will tell you.
The fluid, like shorod says, is most likely old and contaminated and needs to be replaced anyway.
The caliper needs to be looked at and nobody can do it over the internet.
The same thing is the rotor.
Good luck,
Sam