With the stardust, I actually rebuild the heads myself and it really isn't that difficult to be honest. If you dont want to get into all of that you always just
buy heads.
Note: I use the stardust V3 and I got it from this here
DesertVapes Electronic Cigarettes and Supply
This is just the link to their website but I'm sure you can find your way around, This is a great site.
Oh yeah and what kind of battery are you using with this if you don't mind?