I would suggest that you join the Omega forum over at Watchuseek and post pictures of the watch when you get it back, along with any estimate that that me be included with the return from Omega. Knowledgeable folks there can give you some advice in regard to the costs and reasonableness and/or perhaps a local repair person as an alternative. I have to believe the cost you were quoted includes some level of mechanical and/or case repair to reach that level of expense.
good luck.
good luck.