Check to see if you have a farm supply store nearby. They should be able to sell you a floating stock-tank heater for under $25. It won't keep the pond completely ice-free, but it should make enough difference that the waterfall doesn't freeze as badly. The best thing you can do now is try to deal with the ice and keeping water flowing in your pond. If possible, take pics of the ice around your waterfall, and anything that shows where the water ran off. When the weather warms up again, maybe we can help you with changes to contain the ice better so this doesn't happen again.
You might also check with an aquarium store for an adapter to hook your garden hose to your kitchen sink... Then you'll have the option of pumping warm water to try and melt some of the ice.
You folks in the deep South probably never worry about planning for ice and freezing weather, but those of us further North have plenty of experience dealing with it every Winter. We'll help you get things fixed up again!
[EDIT] Now that I think about it, you might not be able to get a heater at your local farm store... they may not stock them in your area! In which case, share some pics when you can and we'll try to help you minimize the damage.