A web site is like any other machine that is used by a company to do business, it requires regular maintenance and has a limited useful lifespan. If you had a company car you would buy the newest one you could afford and would put some time and money into its maintenance. A website is no different.

Looking at your website and the software being used to operate it I see two issues that should be dealt with urgently: 1. the version of the web server (Apache/2.2.15) is very old (released in March 2010) and 2: the version of PHP in which the site was written (PHP/5.3.3) is also very old (released in July 2010). Both are no longer supported by their respective open-source communities and have numerous bugs that have been fixed in subsequent releases. If you have someone responsible for keeping the site updated then they are not doing their job; if there is nobody maintaining the site then you need to find someone to do it.

Make sure you will not have these issues with your new site.