If your website is lacking the web presence that it needs to be successful then hiring a company that specializes in SEO services could help.  Because these companies are specialists in their field they know what works and what does not work.  They also know how to apply this knowledge to your site to give you the results that you have been lacking for so long.  In addition to tweaking your site to perform well in the search engines they will also optimize your site so it loads quicker, and has a proper navigation and internal linking structure.  All of these things combined will ensure that your site is performing at its best and will ensure that you see long term success.