Watch has a very 1950’s look to it. The case and band would seem to be aftermarket and not made by Omega.
Value would be in gold content and stones.
Unfortunately, these tiny women’s “cocktail” watches are not in style today. Because of their size, they can be very time consuming (read - expensive) to service.
Best bet for maximum value would be a jeweler would could evaluate the diamonds properly.
Hope this helps,
gatorcpa