well your lense is 42 mm , you can actually get 45mm mounts, two piece i would get, but if you require extra space get the 56mm high mounts, you can get these of jsr for £14 called accushot if the scope tube is 1inch you will need 1 inch mounts if it is 30mm you will need 30mm mounts your rifle i think has standard 11mm dovetails so look on jsr

P.s did you get the foresight off