[twenty twelve] Quick tips to change colours

Hello, I’m building a WordPress-based site for my girlfriend’s company but I want to replicate the colours of existing website.

The current website is here: https://www.self-storage-hampshire.co.uk/
The new WordPress version is here: https://dev.self-storage-hampshire.co.uk/

How would I change the header colour to the dark red?
Can I change the menu to be black with light grey text?
Are there any other tweaks I could make to improve the site’s look?

Thanks in advance