Object following mouse in masked area only

I’m sorry to bug you but i’m flash noob trying to learn smth and i want to ask you a thing or twho here till i get my book.

http://freeweb.siol.net/tomaztr/default.html
here’s the page i’m working on (with no comercial intentions) and i didn’t have much problem making simple animations, but now i need to do lil action scripting and that’s where i suck the most :diss:.

I want you to concentrate on that yellow piece of paper behind the hole, with smth written on it. If you move your mouse you can see what i had in mind, but now i would like to limit that action in masked area only, or if that’s too complicated i just want to limit action for certain _ymouse (for example only from 100 to 200 pixels)

mouseInterval = setInterval(premik, 10);

function premik() {
    papir._y = _root._ymouse/5-10^(-1)
    papir._x = _root._xmouse/15+5^(-1)
}

Here’s what i made from that magic mouse toturial and couldn’t find any solution to my problem in hours of trying.
Thanks for helping and i’m terribly sorry if i made similar topic to any existing.

Wisse

p.s. do you recomend any good book where i can learn flash from?