Hi
Welcome to LE!
If you already have a setup for the hh, then I wouldn't see a need to go with a kit as you probably already have the odds and ends that you start with. Pick up what you need to upgrade first, so find a torch -
ArtGlassHouse has some good prices for the torches...and I would get the hoses there too if you get the torch (they can check the hose fittings are the right ones for the torch).
Regulator/s - I would get at
Devardi. Good price and works fine, (I bought mine there). They also have the best prices on marvers, rollers, fiber blankets, and not bad on mandrels- lots of variety. They have some torch marvers too, those are new so I don't know how they work but you can always pick one up later - I don't think that is a deal breaker.
Oxycons -
HobbiesforUs can be recommended sometimes (lowest price and reliable), other vendors as well here, but they are more expensive although they have warranties. A lot of folks pick them up locally from Craig's List, so there is some advice on threads here about what to look for.
If you want to do tanks, many recommend opening an Airgas account to keep the prices down, as you go through them fast.
You're going to have fun, enjoy