The theme IS very slow and tests with YSlow and Firebug don't really indicate any one reason why this is. However, with enough experience looking at web pages you can see some trends.
Something to think on: you might benefit from learning to be more specific when reporting on issues like site speed. What is slow - load time or animations? Which pages are slow - just the front page or all pages? If one page is slower than others, what's different on that page than the others? If you can ask and answer these type of questions, your troubleshooting abilities will take a big step forward.
How can we test? Well, click on the About link in the menu and see how an interior page loads. As it turns out, the interior pages load quickly once the server responds. So that supports our theory that the slide might be an issue. However, loading the featured link slows us down again, albeit not as bad as what the front page. So what's on Featured that's different? For starters, Featured is a category archive so the WordPress Loop is running to pull up the posts. While I cannot see the Loop code just by looking at the front end of the site, I would bet beer money that the theme author over-engineered the PHP for the loop and that may cause the database to respond slower. The other thing that's different on the category archive is the presence of featured image thumbnails. While these should present no big challenge, mistakes in theme coding can cause WordPress to wait on the image longer than strictly necessary and that holds up the rest of the page render. Drilling down to individual posts does seem to confirm this as each post with an image takes a lot longer to load than pages without images.
So we've identified possible culprits as the slider and featured image/image processing. Without seeing the theme code, it's hard to go further. However, you can probably disable or remove the slider yourself and test again. My educated guess is that the theme will start responding a lot faster.
Finally, make sure you take the proper steps that any WordPress site owner should be taking to speed things up. Use a caching plugin, minify code, and optimize the environment as best as you can to give WordPress a boost.
So all that being said, I agree with John Conde above: don't waste your time fixing a bad theme. There are plenty of others that look like this and are responsive and can work with WooCommerce.