Hi there!
I have recently completed a very similar project for my client where i had optimized/improved a CMS Website.
It would great if you share the site link for analysis then only i will be able to tell you an estimate timeline for accomplished this project.
I have been working as a professional web developer/designer for 7 years now, and familar with Wordpress, PHP, Mysql , Joomla, Magento, WooCommerce, Photohop, HTML, CSS, Jquery, Javascript, Bootstrap, theme and plugins customization and development.
I am available on chat box. We can discuss there in details in a quick way, if you are interested.
Looking forward for a positive response.
Best regards,
Abhishek Saini