Twenty eleven search box site on top of header image on mobile

I am using the twenty eleven theme.

My site https://www.orientalrugcleanandrepair.com looks fine on my PC screen, but on the iphone version the search box displays on top of the header image rather than below it as it does (correctly) when viewed on a PC.

By the way, I’m not a coder and hope I can fix this with just WordPress theme settings. But I’m deperate enough to try a code hack if someone can give me a pretty specific code example.

If you look at the site using an iphone you’ll see a second problem, involving the background image filling the right half of the screen, but I have posted that question separately.

Thanks for any help!