I got mine replaced at Evans Tires. They did it very fast same day. You can call them in advance to have them order the part so it can be there when you take your car in.
I would not risk having someone who says they know what they are doing start "fixing" things a shop is best and try to go to the same auto shop for all your needs.
Don't drive your car much you can blow your engine on a bad water-pump.