The house and stairs are exactly where they were in 1973. Nothing was moved. The stairs take you to M Street, at the bottom. There is even still a gas station at the bottom, just like in the movie.
The stairs ARE next to the house, just not as close as they appear in the film. That's why they built the facade on the real house, so that Regan's bedroom would appear closer to the stairs.
P.S. I also prefer the writer's cut (the version you never saw), to the director's cut (theatrical version) of the original, and most people vehemently disagree with that, too.
I think 3 is the best one. In fact, it is my favorite horror film. Love it. It's the only one I'm interested in getting. I already have the first, and the others are of no interest, whatsoever.