Add an option to a Child theme of Twenty Eleven

I developed a child theme of Twenty Eleven. I need additional theme options, so i added a theme-options.php file inside my child theme’s folder.

However, it appears the option page is still the 2011 theme’s option screen. I can’t either replace or add another one.

Question: what is the correct procedure to add options to a child theme?

In case you wish to see the code, here is my theme-options.php code.