Create full width header image & add heading over image in wordpress on post template

General information for the website: Marketing Consultancy
Description of requirements/features: All pages have been designed apart from the post template of my wordpress website. I have uploaded example image, heading, content & layout but would like the header image to be full width at the top of the page. I've added custom CSS to change the display of this template to not show the original header as this wasn't customisable. Now the design is almost there as desired i just need the header image to be full width and full responsive and heading to appear in white in the same 'Raleway' font as the rest of the website ontop of the header image and not below where it current sits.

This change needs to be a change that will appear for all new blog post pages I create as much as possible.

Example of a live post page is: http://letstalkstrategy.co.uk/coming-soon/

I want the header to be the same size as the header images on all of the other pages i.e. http://letstalkstrategy.co.uk/blog/

Can the URL structure also be amended so that all blog posts have the following URL structure: http://letstalkstrategy.co.uk/blog/coming-soon and not http://letstalkstrategy.co.uk/coming-soon/

Again I'd like this change to reflect all new blog post pages created and not just created for the one live post.

I would ideally like this job completed by end of tomorrow.

Thanks
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