The saddle is trashed. The other rail will most likely break soon anyway too. It's not too hard to find a replacement Hinault edition Turbo on eBay. They pop up regularly for auction and actually sells usually for less than the standard turbo model which is identical except for not having the Hinault label on them.
You might consider getting one with carbon steel rails. I would think the rails would last longer on those for you.
A good welder could weld it for you and you could then hand file it to the correct shape and size. I don't know if it would hold for any length of time. It is possible the weld would be stronger than the originall. A good welder could probably tell you if it would hold.