It sounds like its just being used to hold up the car while the other tires are being changed. Anyway, you should easily be able to get a wheel/tire from any salvage yard and depending on the condition of the tire, you should be able to get one real cheap and either keep the tire or put your own on. Full size spares are definitely a good idea, I use one of my old E1's now, I got caught once on the interstate about 100 miles away from my destination and had to use the spare, I only pushed it to 70(limit was 65) and still had people flying by me.
