Little mods to Opencart extension

I bought an Opencart extension. [login to view URL] I like mod it in this way: 1) in the cart each option checked must be a single product example : t-shirt XS green x 3 t-shirt XXL green x 2 2) if possible delete the checkbox input but with the price calculate automatically displayed. 3) when I add a product with option color size table it add only the option price (now it's working in this way ma anytimes there is a error) I like a developer with opencart experience