I think you will want to optimize for the keyword phrase bumper stickers. What you have now is very weak:
Title: 1: 11: 18.2%
Body: 1: 410: 0.5%
H1/H2/H3: 0: 9: 0%
Links: 0: 288: 0%
Bold: 0: 0: 0%
Meta description: n/a: n/a: n/a
Meta keywords: n/a: n/a: n/a
I also am a bit perturbed by the scrollers. Maybe something slower, or something that only scrolls when the mouse rolls over it. I also would change the size of the sun in the header to make it line up with the menu below it.
I took a lot of your recommendations into account. I removed the scrollers and replaced them with some logos and fixed links. I may swap the pictures out for something that shows designs for each of the categories. Maybe 3 or 4 stickers shrunk down to fit in each image so people know what is being sold.
I made the header smaller and updated it. I also changed the navigation menu on the lefthand side. I think that will be easier to navigate than it was in the past.
I'm left with a bunch of white space on the righthand side. Not sure what to put there. Any suggestions?