Change header on template

Hey there

First of all thank you very much! people like you have really simplified my life! I installed a theme I purchased at theemeforest here https://danglersden.com/test1/ … Im working on a new site for the wave hockey, their current site can be seen here https://www.wavehockey.ca/ … The owner loves the new site so far … he wants one thing changed … kind of a game breaker. In the header of the theme there is a spot for a logo and a spot for a banner. He wants that banner to be his logo and stretch across the entire header like it does on his current site. Is there a way to remove the small logo and make that banner larger? I need it to fill the entire space, or perhaps even centre it in the header space.

Any chance someone can help me out?

Thank you very much in advance