for that much, I would just get new seats, but thats just me.
Might want to look into a leather upholsterer, just to see the difference in quote. making a cover is no different than making a leather jacket, except stretch fitting the cover, and the thread they use is more durable than what they might use at the shop you went to .
but the amount of labor and materials, it sounds about right. Maybe on the high side a little.