Child theme for twenty twelve on WP

Hi there, I looking for a professional CSS/HTML5/PHP developer who's really familiar with WP to make these little changes. I want this modification to be on a child-theme for twenty twelve theme, you should know what theme i'm talking about here. These changes are only in the way the single post page and the category/tags page look like. All are explained in the attached images. Please ask me if you have any question. I need the modification to be exactly as shown in the attachment images, or as close as possible, and I need the design to be clean and responsive for all devices, with the basics of wp development. Please note: the red and blue lines and texts in the attachments are for explanation only, I DO NOT want them in the modification, just to give you an idea of how tables and divs should look like and where. they're 3 images, one for single post, one for category/tag pages with notes, and once again without note to see it clearly. Thanks!