Contact me and I will email you the new curve graphic. Please be aware whenever there is an update to this theme, you will have to keep replacing the curved graphic, otherwise, if you are using a child theme, then you can upload this image to your child theme images folder and then copy over and edit the header.php file. But email me directly and I will send you the png image. If you have Photoshop, I can send you the PSD file so you can make different curves with different colours if you change it later. Do you have Photoshop?