Just can't seem to get right

I can't do math, I can't get my numbers to add up right, I can't convert all these fractions, I can't get my inches and feet right GARRRG!!

what has me so distraught? a staircase, yep a staircase. The short story is I have a doll house, it has no staircase, I need to build one. Do you have any idea the math involved in figuring out the angles, the tread depth, the riser hight and the stringer run? also it's not a straight stair, there isn't room oh no it has to have a landing and a corner and such, I am tearing my hair out, I'm sure there is a nifty program that could do it for me in "real" scale, but what about in 1/12 scale? uh huh not so smart now are ya :P

Before you go thinking I'm to old to be playing with a "doll house" you should know it's a scale miniature, a 1/12 scale model IE 1foot in real life = 1 inch in it, everything is to scale.
The long story(if you care to hear it) is that my Da built this house for me when I was smaller, it was wired (yes it has lights) furnished and decorated enough to please little me and muchly loved for many years, I played with it for hours. When I grew up a bit I decided it needed to be properly finished(better furniture, nicer decorating etc) so round about 15ish I got into it and did quite a lot but growing up got in the way and my house has been sitting in my parents basement ever sense I got busy planning my wedding(winter 2000)
Now the miniature bug has bitten me again and I'm making lists of things to fix, replace, repair and finish. There are floors to finish and redo, lights to replace, base boards to add, perhaps some crown moldings, the stairs to build(if they don't drive me crazy) small touches everywhere, it's something I really get into and it'll keep me busy when Styles is away again.

Want to see it? just ask and I'll take pics of this disaster in progress.