Try get across to the Zambian side at Livingstone, there are a bunch of hotels, more activities and the view of the falls is better.
Southern Sun hotels have the Zambezi Sun right at the falls, 5min walk and through the private grounds and you are at the edge of the falls, slightly higher priced, but on the same grounds is the Royal Livingstone, 5* and worth every penny.
There are a bunch of other hotels and all varying from 5* down to backpackers lodges so the options are there.
My wife and i did trips to Livingstone 4+ years running for min 5days per trip and we did not run out of activities and things to do...
Take
@Bruce's advice and do the helicopter rides...
Go walk with lions, cheetahs, check out the crocodile farm, elephant back rides, microlights, do a day trip to botswana if you havent had enough of the wildlife yet, they have rhino at the musi-oa-tunya national park (last time i checked), got fishing, do a gorge swing, bungee jump, zip line across the gorge, check out the curios and all that stuff, not sure what the livingstone museum is like anymore and whats in there, good eateries in livingstone town. take a river cruise with the Zambezi Queen or one of the others.
Go to the Royal Livingstone for high tea on afternoon around 16:00... my missus enjoyed the serenity at the Royal.
Zambezi Sun Hotel has the activity centre which is the kick off point for most of the activities offered, buses run from there to the town and the activity locations.
Friends of mine own a travel agency with offices country wide and they can give the full range of activities and options etc, they will put together a custom itinerary and so on for you if you need one.