Different design for Joomla site

Hi Designers, A client wants to have a different design of his joomla-site, because he doesn't like the original one (designed by someone else). It's a website for a gardener, which makes gardens for the middle and high incomes. They are not satisfied with the website now and want something else. It's made in joomla, and I prefer to keep that CMS. But I don't want to have that 'same as every other standard joomla-site' look and feel. My own website is also made with joomla, but doesn't have the standard fonts and so on. Maybe you guys can make something cool for this client. If so, what will this cost me?