You`ll have to look at your website and objectively determine if there`s really anything of value. If your site has new functionality that your competitors don`t you may want to keep the code and license it to your competitors. If you`re code is not readily visible by visitors you may be able to protect your code as a trade secret and just skip formal copyright registration altogether. Either way you`ll be able to license the code with a good licensing agreement.
If you don`t have any intellectual property rights you may just want to sell the domain or the site altogether. I`ve never worked with a broker before, but a straight website sales transaction shouldn`t be too difficult to do. I`ve negotiated domain name/website sales agreements for cilents before and it usually doesn`t take a lot of time to close.
Best of luck!