Some truck stop tire centers might still have a patch that large,(more commonly refered to as a boot), or at NAPA . If your only going to use it as a spare to get by, boot it and then run a tube, you'll also need to rough buff the area and clean it real good with the special tire patch cleaner, or use carb cleaner, or the like, be sure you let the glue dry long enough,(about the time it take to smoke a grit), and use the stiching wheel on it for a while from all different directions. Also do not forget to talc (baby powder) the inside of the carcass berfore installing the tube(also doesn't hurt to rub it all over the tube). Then look for a replacement tire on CL.