Header Banner Hiding Behind Menu

Hello, I have been working with Shopperpress for a few years. (https://sueswrapskirts.com/) We have version 7.1.3 up on the site and I have always used the header banner to place a image up of text. Now it is not working (well, it hasn’t been for a while) and I just discovered that the header banner is there, but it is hiding behind the menu. I found this out by using the “Inspect Element” tool in Chrome.

How can I get the header banner to show above the menu bar and how can I get it to float to the right (it is floating left now)?

I do know basic CSS and HTML, but cannot find the right files to edit.

It is not the plugins, I disabled them all and it was still hiding behind the menu bar.

Thank you,
Sarah