Due to my wife getting a new bike through a cycle to work scheme, I'm thinking of getting my old Marin Palisades out of storage. I think it's about 18 years old but I can't quite remember how old I was when I got it. On my last trip out on the bike I binned it big time, ending up with 2 buckled wheels and a badly bent rear deraileur, it's a shimno deore 300 LX (I think) 7 speed. Everything else on the bike works fine and the wheels are easy enough to replace. I'm not sure about the deraileur, can I buy a new shimano deraileur or will I have to get an old one? The shifters are Shimano STI. Any help would be gratefully received.