Yes the Better Boy will soon outgrow any cage like that so get a new one on ASAP to avoid anymore damage than necessary. For indeterminate varieties 8' is common and many will grow even more.

Those of us that use cages find 6' cages to be adequate as the growth that tops that just drapes back down over the outside of the cage. You'll find many discussions here about the various types of tomato cages available but these ring type things are generally useless when it comes to tomatoes. Save them for peppers, eggplants, etc.

The damage done to the Early girl isn't fatal to the plant. New growth will develop from the nodes below the damage. Just carefully trim off the damaged parts. You might lose some production but indeterminates are really tough guys and recover well in most cases.

Dave

Many people make taller cages by making a ring of concrete reinforcement wire (crw). How available crw is in smaller lengths, I don't know.

Some people have used a second small cage, inverted, atop the first, usually attached with cable ties. How successful that is may depend on the gauge of the wire used in the cage uprights. [The times I've seen this method used, it's always been with self-watering containers, usually the hand-made ones.]

This link evaluates many different methods of supporting tomatoes:
http://www.mastergardeners.org/picks/tomato_staking.html

Probably the easiest and cheapest way to get tall support is to buy tall stakes. You'll want to bury a foot underground, so consider that when deciding what length you need.

Another option is the "Florida Weave" (I've seen the term "Texas Weave" used; I assume they're the same). In the first link above, it's called "Post and Twine Method" -- and badly described. See number2's post on this thread for a diagram; when I've used it, I weave around each plant individually, not two at once (they'll get mixed up enough anyway without my bundling them together in twos!).
http://forums.gardenweb.com/forums/load/tomato/msg041148319850.html?14

I have a neighbor whose late husband built tomato frames out of wood; most of her tomatoes are Roma-types, so the frames are about 3-4', but you could make them taller. Basically he just put two rows of stakes into the ground (I think they're 2x2's), then added occasional horizontal cross-pieces at different heights. This is a permanent installation.

Here are the instructions for GWebber qaguy's homemade PVC cages:
http://www.feldoncentral.com/garden/tom_pvc/

I have successfully saved plants in the same situation with the tallest available bamboo or hardwood stakes. Hammer 3 evenly placed around each cage and tie the cage to each stake. I just used string or velcro plant ties. The stakes anchor and support the cage so it doesn't fall over with the weight of the plant and tomatoes. As the plant gets higher than the cage you can tie the plant to the nearest stake. Make sure you pound the stakes into the ground well. If you want to add another inverted cage on top you can try that and also tie that one to the stakes. I wouldn't personally go with just the cages because I have not found them to be sturdy and stable enough for the weight of the fruit laden vines. You also don't risk breaking more branches off if you don't try to get another cage on top. Buy a bunch of extra stakes, they are not too expensive, and you can add an additional stake here and there if you need it as the season progresses. I grew tomatoes for years with just stakes, 3 per plant, but you need the tallest and heaviest duty bamboo or wood, I think they are about 8 feet.

Thank you very much for your responses!
My tomato plant is doing great now, and is growing so vigorously it's as if nothing happened at all.
I have decided to go with a support method I found online. I placed the tall stakes around the cage, tied together at the top. That way I can leave the small cages in place and continue to let the tomatoes grow.
Next year I'll find another solution for those cages, or grow only determinate varieties.
So far I have about 10 set tomatoes. I can't wait for my very first taste of a garden-fresh tomato! :)

Thanks again,
GreenSerenity