App icon and splash screen for iOS Game

I'm looking for a graphic designer to create an app icon and splash screen for an iOS game. I have a vector mock-up that can be used as a starting point. I am looking for someone to take this initial mock-up and turn it into a polished and great looking final product. I like the bright colours but the characters look awkward and the overall feel is of low quality. I also like subtle shading and gradients. Key items: 1) Improved character appearance to have more accurate human proportions. To look more natural/realistic for a cartoon. 2) Improve the composition of the background with better shading, colours, lights, effects, etc. 3) Improve text on splash screen. Perhaps with larger font, having a slight gradient and a border with a different colour and a subtle drop shadow. If you have other assets that could integrate well like textures of clouds, or trees for example that would be good. If you have ideas i'm eager to hear/see them. As a final deliverable I would like a vector based file. Thanks!