Some better formed thoughts:
Layout - I like it, but maybe consider having your central panel as a solid colour (or at least bump up the opacity) with images down the side, this would improve text legibility which isn't great on some pages. I'd also think about narrowing the central panel as your line length (more on that later) is very long.
Contrast - That yellow on blue is really tough to read. Keep the colours, but explore different tones.
Collor is very useful.
Text - Keep the serif font for the headlines, but change the paragraph copy to sans serif - it will be much easier to read. And on line length, it's massive so tires the eyes. Smashing Magazine had a very good article on this
here, in fact they're a very good resource in general (though probably overkill at this stage).
Pedantry - I hate those images that fly in from the side on a couple of pages, but that's just me.
RE: Speed, I think that's probably because it's a Wix thing. Do you know what sort of code it actually outputs, ie what you'll be putting onto your server? It seems a few folk have had browser issues which is not good - this is an international site which needs to work everywhere, and on as much as possible.
Hope all that makes sense and doesn't sound too harsh - you've made a really good start and with a few tweaks will have something neat. Happy to answer any other questions.