There's not a great deal of aftermarket stuff for this pistol. I've had mine for about as long as yours. Only thing I have bought are two mags (Walther) and an IWB holster (DeSantis Sof Tuck). I've seen the laser from Walther ($120+) but I don't see myself buying one.
As far as the sights go, I use a six o'clock hold on mine and it shoots pretty much dead center.
I really like this gun, but I'm looking to trade it in for an LC9. This might become one of my "wish I would have kept that gun."