Atahualpa child theme function php

Hi all,
My php skills are seeming to be lacking for this...

I'm doing a site that is including a hack to the Sidebars widget code in functions.php. More precisely, after
// Sidebars:

// Register additional extra widget areas:
<next 15 lines>

I want to move that section to the child functions.php so that it survives ATA updating.

I can't figure out the proper unhooking from the "original" functions.php and inserting the same (but modified) section of code into the child functions.php

Please hit me with a clue stick someone!

Thanks!
Ken