Every writer is aware that the job doesn't end with just writing a book. There's a heck of a lot more that needs to get done; editing that seems endless with back and forth correspondence with your editor, cover approval, layout approval, and printing.
You don't have to be particularly outgoing to get on the media's list of dependable guests and resources. Just let producers, hosts, editors, bloggers and other media decision-makers know that your schedule is fairly flexible.
Of course, you probably know a 12-year-old who can design your site. Don't hire him or her. There are places to save a dollar, and website design and implementation isn't it. Your reputation, as an author, depends on how good you look online.