Where to begin.....
I know, fire your web developer immediately!
This is how your header renders on my dev laptop in firefox, it also has the same issues in chrome as well.
Notice how the customer support section is pushed down?
Also please use standard fonts, hint, "Oswald" is not one of them.
Your page size is unbelievably huge:
For comparison, the home page of Amazon.com is 62KB yours is 1664KB!
For some reason you dev is using pinterest as an image host, don't do this. either buy an image hosting package such as aws or another cdn or run them off of your own servers.
Last but not least is:
Probably for shady seo purposes, your dev has decided that it is a good idea to list every product with full description and images in your catalog on your home page and then set them to not be visible via css or jquery (I didn't bother to look how). The real reason why your site is slow is because of this very reason, looks like hundreds of items with images, jquery, sharethis widgets and everything else... on the home page /palmface!
Here is your home page as it is rendering, I stopped it mid stream so that you can see what is going on and the reason why your page is 1) slow, 2) unnecessarily large.
Let me know if you have any questions.