Welcome. Did a manual come with your 357? You can get the part numbers for the ejector rod, housing, spring and screw in the back. If not call Ruger 603-865-2442 they will ask for the serial number and you can order the parts and ask for a manual. Ask for records and they will tell you when your gun was shipped from the factory.
You can get parts from Midway and Brownells also but shipping should be cheaper from Ruger and you need a manual.
Let us know. Lots of people to help here.
Eric