Wp Wordpress

i have a movieclip 70 px height (orange color in the picture, registration point in the BL), it lies inside another movielip on y = -10.
can someone write me how could i adjust its height (which should be between 0 and 70) based on mouseY.

here is the picture:

and how could i calculate volume based on its height, volume ofcourse goes from 0 to 1, so how do i make this happen? :p

thank you!