Header image responsiveness

Hello, I'm using the Intuitive theme to create a website for a client and am having issues getting the header to display properly on mobile devices. I'd like to know if I can possibly have an alternate image display on mobile and if the overall site layout can be changed so that more of the page content is visible when the browser window is at 100%. I have the site set up at staging.sarikessler.com if someone could please advise. I will recommend that my client purchase the Pro version of this theme, if these issues can be rectified. But, as it is now, the theme doesn't seem to be as responsive as what the description has claimed.