Ahhh, yet another horrifying Tale From the Taurus Crypt!
I suggest that you try to find aftermarket sights for your pistol, rather than wait upon Taurus's tender mercies.
Why replace a breakable plastic sight with another breakable plastic sight? Buy a set of metal sights, and have done with it.
Brownells lists a replacement set of Williams's Fire Sights, with light pipes, but light-pipe acrylic gets brittle over time.
Instead, take a look at: http://www.opticsplanet.com/trijicon...sight-set.html