Fiberfix spokes can be bought (among other places) from www.adventurecycling.org. Click on "store" and then "tools". I've bought a couple but haven't use one yet. They are supposed to work very well, and I'd guess would take 10-15 minutes to install on the road. They do come with good directions.

Hopefully you had two damaged spokes that have now been replace and you won't have any more trouble.