Make My WordPress Theme Look More Beautiful!

Hello! I have a WordPress with multiple options, I hired a freelancer to code the entire theme from scratch according to my requirements and we have multiple color templates in theme but it doesn't look professional enough! I'm looking for someone to play with CSS/design and make whole U/I simply awesome! There are total 5 color templates (css files) each are of different colors... You have to work on those files. We do require some minor changes in theme options as well so you must know PHP too.