If you want to make socks, you may need to buy fixed circular needles instead of (or in addition to) interchangeables. The Knitpicks interchangeables only go down to a size 4, but they do have fixed needles in smaller sizes. I thing Addi Clicks also only go down to a 4. HiyaHiya interchangeables go down to a size 2, which may work for socks or they also have fixed needles going down to teeny tiny sizes (like 00000 or something).
Hope you find some that you like!