There are the following possibilities:
- first try the repair it by a local watchmaker. It could be an easy fix.

- the cheapest solution: Asia 6497 clone but this is going to be a visible issue.
- try to find the same movement from a rep TD. They sometimes offer these movements separately or on RWI.
- try to find on eBay an UNITAS 6497 in a pocket watch for max. 50-60$. The item should be in US or Canada in order to avoid high shipping cost.

Maybe I have missed further solutions.