cant find garageband instruments macbook pro??

i purchased my new macbook pro a few months ago and i never realised but not all the instruments are avaliable to use, well i cant find anything more than the standard ones (see image). why is this? i spent so much money on this laptop i expected to get the full version. i checked in my application folder to see how much capacity my garageband program takes up and it only takes up 375MB so i'm assuming this isnt the full version? also, below the instrument list theres an icon (see image) u can click which shows numerous images of different instruments but whenever i click on a different image, the instrument itself does not change. how can i broaden the different instruments avaliable to enhance my garageband experience? thanks a lot, appreciate it