The mr2 mk3 spare wheel won't fit your car, as the MR2 is a 4 * 100 stud PCD, where you have 5 stud on the DNA cars, and I believe yours is 5 * 100 PCD (same as mine)
So that won't work... plus, if you place a small spare on the car, it won't fit right and you are liable to scrape the front or back of the car, as your wheels are 19" and not 15" live the original MR2.
You can buy the spare wheel lid off eBay, if you haven't get one.. they fit ok