I came up with many half baths, but not one that big.
here is what I have: A Standard Half Bath size 4 x 6 with sink, water closet and a closet will run about $2700 labor and material.
here is another:This is a full bath, which is not what you desire, but its 8 x 10 has all you want but the tub, labor and material $8000.
Now, this will vary with economic regions, but you might be looking at about $3500 - 4000 for this project.
get three bids and make sure that before anyone comes out that you have all the things you want and the size is set and nothing is changed between each contractor. This job will require a carpenter and a licensed plumber and electrican.