Look up the manufacturer's website, to see if that company is still in business. If so, see if they have something that is almost identical to it. If no luck there, try listing your "wanted" ad in Craigslist. In your ad, be very specific to the name brand of that tile, along with the product number, if available. A photo would be nice, too. If you are lucky, someone may have some leftover tile exactly like that, after doing their tile job. Craigslist covers tons of households, so you might get lucky.

Good luck