customizing theme

Hello everybody, let me first tell you about my project. I'm working on setting up a website where hairdressers and people who want a haircut at home can meet. So the idea is that hairdressers can create a profile on the website so that customers can view the protflio's and make a choice between one of the hairdressers. When customers enter the website they should immediately be able to enter their zip code and get a list of hairdressers in his region. I have found a theme that reasonably fits my needs. This is a link to the theme [login to view URL] . Only entering a zip code is not possible. With this theme customers can choose from a preconceived list of places or topics. as described in this link: [login to view URL] . This should be changed to a box where you can enter your zip code. Also the hairdressers need to fill in their zip code when they make their profile. The zipcode in the hairdressers profile and the zipcode search engine on the frontpage should correspond. My question is whether anyone can help me to adapt this theme by replacing the list of predefined regions with a plugin for searching by zipcode or custmozing the theme with a child theme. A better idea to provide in my need is also very welcome. I hope to hear from you soon!