allows along button cart customer fabric fabrics item link order page quantity replaces require

On a test page at this link

http://www.bunkbedking.com/protect-a-bed-pillow-protector-std-test

When I add to the cart different fabrics, when I order the second fabric, it replaces the first fabric in the cart - it does not add it to the cart along with the first fabric.

Also, can I set up an add to cart button that allows the customer to enter the quantity of the item they require?