I found the piece of code in the header.tpl file but couldn't figure out how to replace it, since im not that good in scripting. But i did manage to do it using only CSS, it might not be the cleanest piece of code but it works!
.categoryname .logo {
display: block;
box-sizing: border-box;
background: url(*img link*);
width: 350px;
height: 99px;
padding-left: 350px;
}