Water is usually the best choice, because it's free (if you're drinking tap water) and has no sugar or calories. But most healthy people can get enough fluid through the beverages they consume every day. These can include water, fruit juices, coffee, sodas, iced tea, and other drinks.
A Cooper-produced non-speed rated passenger tire's maximum speed is 137 km/h. Tire speed ratings do not imply that vehicles can be safely driven at the maximum speed for which the tire is rated, particularly under adverse road and weather conditions, or if the vehicle has unusual characteristics.
The donut spare has a speed limit of 35 mph, you have to follow that-even when new. I think if it holds pressure (I think it is supposed to be 60 psi for the spare) and you stick to the speed limit and just drive to the shop to fix your tire, then you should be fine.