I disagree. If your shop (
http://www.atafa.com) has been online for a while and people actually buy the wristbands from
http://www.atafa.com (which I am guessing they do), then you definitely should create and promote the product within the
http://www.atafa.com website.
It should be much easier to get a page ranked under the
http://www.atafa.com domains than building a whole new website.