You will have to make up a to-scale side view of the house, stairs and landing area at the bottom. Then draw in the railing, and you can determine how long the railings will have to be.
In my local Menards Hardware they sell railing by the foot, you buy the top rail, the bottom rail, and the number of uprights you need. There are endcaps/filials that finish off both ends of the railing.
Embedding the top and bottom end posts into the concrete will require drilling holes in the concrete and that will take a considerable amount of time and energy. The top and bottom rails can also fasten to the house itself for added rigidity.
A lot of work, but $1000 seems high. If you go that route, get reference names and addresses of previous work and check them out.
Take a tour around your town/city, see how other similar railings are installed, take pictures.