a club visit is a good start, someone will not only tell you how to keep the pistol tidy, they will show you too!!!
the hw45 has a very good reputation as a pistol and they are well made, to age them, i think you just email weihrauch direct with the serial number and they should get back to you with an approximate manufacture date.
if you get into the target shooting malarky - Pad.E has organised a postal competition for the bbs's pistol shooters so even if the club scene isn't for you, you can still have a go and see how you fare against others and judge your progress the more you shoot!
good luck with it!