I have seen your site and you have an excesive amount of files (scripts and images).
Two easy Joomla optimizations:
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Reduce script (JS) count from 11 to 5 or 4. I recommned to install this joomla plugin for compression and packing: http://extensions.joomla.org/extensions/core-enhancements/performance/site-performance/7350
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You could add a lazy loading plugin for improving image loading. I recommned this extension for Joomla: Lazy Loading Images
As Ryan mentions I would hire an experienced developer, but meanwhile this two plugins will make the difference.