yea i would go to homedepot or lowes and soon as you can and pick up one of these until you replace the tank or repair it. you can order a whole top brace but it may not be worth it depending on the shape and age of the tank
mike your going to have too make your own brace. depending on the thickness, i know lowes sells stainless U-channel from 1/4" - 3/4" get a 24" piece cut it in half. get a piece of threaded rod and 4 nuts connect to the U-channel instant brace