Billboard Graphic Enhancement Needed

I have an existing billboard design whose graphics need a quick yet professional polish. The layout and copy are staying exactly as they are; what I’m after is a visual lift that comes from enhancing the current artwork itself... (Budget: $10 - $30 USD, Jobs: Adobe Illustrator, Adobe Photoshop, Graphic Design, Image Processing, Logo Design, Photo Editing, Photoshop, Photoshop Design)