No joking but look in teh golden pages and pick out a builder, there is a good chance that he will come around have a cup of tea, agree to do the job, turn up on day one and dig the foundation, turn up on day two, build half the wall and then look for some money for more materials and you'll never see him again, but you'll have your half wall. Plenty of posts here on that subject.
If you have solid ground floors this will not be problem, probably use light weight blocks with a couple of rebars sunk into the foundation for stability.