That's pretty much what you have to do. Also, buy more than one so that when the next strap breaks, you have a back-up that can tide you over until you've bought some more. That way you never have to take a break in extending.
Extenders are expensive, you normally have the initial $150 - $300 outlay on the extender, and then you have to buy regular supplies to replace the parts that get worn out, and these supplies aren't cheap due to the customer's options being limited.
I expect that you snapped the strap when trying to pull it through the head piece right? That's how I broke all of mine, I was shocked the first time it happened but then I realised that they only last for a month or two and then you have to get a new one. This is because the rubber material can only stand a certain amount of times where you can pull it through the slit in the head piece, as it's such a tight squeeze.