Move add to cart button and price on product page

You need to edit your CSS in the config under the tab display.
There, you will find that code:
.hikashop_product_left_part {
text-align: center;
float: left;
width: 50%;
}

if you remove the float:left; the information which is usually on the right side of the image will go under it.

Did you save the configuration with the "custom" CSS file selected in the CSS file option ?

If you want the price to be on top, you will have to edit the view which displays the product page and move the code around. You can do that via the menu Display->Views in the file show of the view product.