Customize an Opencart Theme

Hi, I need an opencart theme customized for a client. The theme was purchased from themeforest and I need it made unique as the client wants to resell the theme. The following needs changing : Fonts Images including buttons Layout of all pages slightly changed Change name of elements and divs etc Slider changed and new product slider added to homepage The admin functionality needs to be kept working and the site needs to stay looking clean and fresh yet different to the original design. You can see a demo of the current theme here : [login to view URL] Thanks.