Did you actually turn on the 120 volt electric heating element switch while hooked to a form of shore power? If not, then you should be OK. If you did turn it on, then as you stated, it's gone.
You can pick up the elements in camping supply stores, Camping World, and even Home Depot.
Don't take this as gospel, but I think the 6 gallon and 10 gallon take the same element, in the Suburban brand. Don't really have experience with the Atwoods.
The original Suburban heating element is 1440 watts, and I think you can easily pick up a 1500 watt one at Home Depot as a drop in replacement as others here have done.. Just make sure it's 120 volt and not 240 volt.
I think KyDan even has some part numbers in the FAQ section here on the forums in the subforum water heaters.
Edit: Here you go if you have a Suburban.
Cheapest price for electric element