Make wordpress header same as site

General information for the website: Media
Description of requirements/features: Hi,

We have a site that doesn't run on wordpress.

We're setting up a blog that does run on wordpress.

We need the design to look the same. We have an include file for the header on our site, I don't know if we are able to just link that so when it updates it updates to the wordpress too?

Also, we also have a small issue with our header that needs fixing.

Need this fixing asap.

Thanks
Extra services needed: Customization
Extra notes: