Rachel:
I think Facebook requires you to have a certain number of "likes" on your page before they give you the simple address of www.facebook.com/(your shopname). I'm not totally sure about that, but pretty much sure.
I think you have to suffer with that long string of numbers until your likes reach (I don't remember of it's 50 or 100), and then your address has enough business credibility that they assign it to you with your shop name.
Not sure where you'd find that information, but I'd Google "Facebook business page address information" and see if that leads you somewhere useful.
Good luck!