Want to change banner size and background color

[RebelAutoWorxs]

Ok I've tried reading the tutorial and still feel like I'm going in circles.

I am running a custom template.

I've tried changing this:

#logoWrapper {
width:800px;
height:300px;
background-image:url(includes/templates/CUSTOM/images/logo.jpg);
background-repeat:no-repeat;
}

in the location: index\includes\templates\custom\CSS\stylesheet.css

by changing I mean 699px to 800px and 289px to 300px

After these changes I still see no change on the site.

I am very new to this stuff so please take it easy on me.

The page I'm referring to is www.rebelautoworxs.ca/index

Thanks