I have this modem but I cannot see how to connect it the Eir Fibre setup , the Eir side is using an Optical Network Terminal using a network cable RJ-45 , the Vigor is looking for RJ-11 .
I think I may have bought the wrong modem .

Yes, you have the wrong modem, a Vigor 130 doesn't handle fibre connections. You should be able to go from the ONT direct to your router.