Top position in Google

Hello, a client owns a car rental company in the island of Crete in Greece. He had several sites designed for his business and most of them are identical mirrors of the same site. The client wants to have one of his sites rank in top 5 (1-5) positions in google for the keyword phrases "car rental Crete", "Crete car rental", "car rental Crete", "Crete car rentals". You will work with one site only but you may use the other ones (mirrors) if that will help you in your effort for better search engine placement. You will have full access to the server for as long as it is necessary, so that you can modify the text in the pages. You will also work closely with the web designer who will redesign the site, in order to optimize the new design for better search engine placement. The client needs results and his term is that he will NOT pay unless he gets the top 5 ranking in [login to view URL] I understand that this is a very strict term but he is determined about that. The client is willing to pay a fixed fee when the top5 ranking will be achieved plus a monthly maintenance fee for as long as his ranking remains the same (1-5) or improves.