Wordpress site speed is very slow - repost

Project Description: I have a Wordpress website that is ranked well but the site runs very slow. It is taking about 9 to 15 seconds to load the page currently, and I need it to move it to move fast because it is affecting the conversion of the website. The website is [login to view URL] so take a look and tell me how you will solve this issue and the cost to do it. Don't just tell me your cost. Tell me also what you intend to do to fix it because I had paid somebody before to fix the theme with the idea that it would be fixed but the speed is still slow. I also can not change the hosting, so that is not an option for me. I should note that I used this site at [login to view URL] to analyze the site and I saw that the Chat plugin was slowing the site down so I deactivated it. I'm also seeing that the social icons and size of the page images also could be an issue. I willing to change the chat and social icons for something that will not put weight on the sight. I will need you to look the plugins also to assess what is causing the problem and to find a solution. I do want to note that I had the previous person find a solution that made the speed fast for 3 days and then it went back to a very slow speed. After you improve the speed, I will need to wait at least one week to make sure that the speed does not change. I realize the the hosting could be an issue, but I will not let that determine my satisfaction. I just need a site that will consistently load within a few seconds, and not only for the home page, but for all the pages. I would like that you find a way to make the site secure from hackers. If plugin, then make sure it does not slow the site. Thank you and Good luck with your bid.