There are omega serial number charts on multiple internet sites if you search. Yours is somewhere around 1910-1915. If your watch has sentimental value, you will need to find a watchmaker who has a good supply of old, scrap watches and movements. I had a small Omega pocket watch from the same era that I needed one wheel for and I finally tracked down a person who specialized in pocket watches, who dug through his stash of parts to find the wheel that I needed. I spent a year on the project and when I was finally done, it cost more than the watch was worth. Unfortunately, I had already showed it to my son and he really liked it, so I told him that I would fix it for him.
Yours is much worse, and a lost cause IMO unless there is a compelling reason that you have to restore this exact piece.