Recommendations for making my site load faster

Hi there,

Here is our site, it runs the Florida theme from Themeforest:

We are getting reports that it's slow, and when I run a speed test on it!/cMTnWM/ it's confirmed, and shows me all of the scripts that are loading (there are a lot).

I have tried a number of caching plugins (implementing caching with W3TC gave me 500 errors twice) as well as minify plugins (Better WP minify and Autoptimize - both caused problems with making the css go awry) so I am really leery of this route, however I'm starting to believe that it needs to be/should be minified.

We've done the obvious thing of making the images as small as we can get away with. I'm thinking I should be looking in a CDN.

Do you have any recommendations? Is there a minify plugin that you recommend that I haven't tried (and why aren't these working for me? Is it the theme? My server?) Is the CDN the route to go?

Many thanks,