Hi, Dana - Welcome over here to the Sewing Forum! This is as good a place as any to post your request for a visor or hat for your pup.

I don't know of any sites with dog visor patterns, but the link below is to a site that has really good photos of how they are made. I bet if you studied the photos, and used a simple pattern for a human child visor, you'd be able to figure it out. You probably don't even need a commercial pattern... here is one on line Fun Foam Visor that is made of fun foam, then covered with fabric.

Come back and post a picture of your little Asta with visor when you get it made - we love photos of completed projects!

Here is a link that might be useful: Dog Gone Fashions