What are you looking for in a workout?
If you are looking for health, you should already be getting that from Swings an Get-Ups. Swings are one of the best things you can do your posterior chain and your back, get-ups are possibly the healthiest full-body movement you can do. Physical therapists love get-ups (those who know them). Of course you have to do them properly, so getting you form checked may still be a good idea. Also, get-up technique has been refined significantly since ETK came out. Check with "Kettlebells from the ground up", your local RKC or possibly youtube.
If you're looking for cardio, you can either work your way up to high rep swings, which are excellent cardio all by themselves, or you can just learn more exercises with kettlebells. The full ETK program is much more intense than ETK's program minimum.
A complex of clean&presses, swings, maybe snatches, pull-ups and push-ups will have you collapse on the floor in no time. But put the kettelbell down safely first.
Considering Swings, you might try to go hardstyle and work on your hip-drive. At the top of the movement, you should drive your hips forward as hard as you can (with your glutes) and contract your abs hard, your body should be completely stiff.