How many frames of brood do you have at the moment Jenxy and how many of stores? I take it that there are no empty frames? With a good five frames or more of brood, you should perhaps be thinking of putting on your first super. This will allow the bees to move honey up and allow for expansion. How many supers, with frames and foundation (or comb) do you currently possess (assuming one hive)?
It is unlikely that you will need a second brood, but not impossible. Your mentor should be able to confirm this. If you haven't got a mentor, I would strongly recommend that you find one through this forum who is both experienced and reasonably local, therefore in tune with your general area and willing for you to flood with beekeeping questions.
I think that the one single book all new beekeepers should read is the Ted Hooper "Guide to Bees & Honey". It is generally considered to be the standard. Unfortunately books reflecting practice in the USA also reflect their different climate and , depending on the type of hive used, supers can be the same sized boxes as the brood box, the name merely indicating the particular usage.
Components for a second hive: floor, brood box, frames and foundation, crown board and a roof would be very good to have available. The last thing that you want is to find that you need a bit of kit NOW and it's a week away with exhorbitant delivery charges because you didn't anticipate it. That was of course the reason for your question.
Others will be along to give you a more precise and better qualified answer than I have been able to provide, but feel that they will express much the same sort of sentiment.