Best Fit Curve [RESOLVED]

[CVMichael]

I want to make a program that will fix a distorted sound, it is not any type sound, it is a tone (which actually makes things easier)

When the sound is too loud, it will be cut off.
I want to decrease the sound volume, and complete (by approximation) the parts that are missing.

I searched on google for "best fit curve", I have found programs that do this, but not for sounds, and I didn't find any source code.

What I want is to have a function where I give the points that I have (that are valid), and I want it to complete the rest of the points based on the points i'm giving it.

If you look at the attached picture you will have a better idea.
The top wave, is the distorted one, and the bottom, is one where I manually fixed one of the "bumps" of the sound.

the part in between the 2 vertical lines is the part where the function should complete.
I want to give the function a few points that are before the left line, and a few points after the right line.

I also found on the internet formulas to do it, but I'm not that good at math (grade 12 math is the last one I took, in coledge math is not required ), I was hoping that someone might explain to me how to do it in a programming way.

Any idea on how to do this ?
Please help...

Thank You.