Hi Nicki, welcome to the fourms
You should be able to mount most Samsung or Pentax (KAF2 and KAF) mount lenses on your camera.
Warehouse Express has a page dedicated to Samsung/Pentax fit lenses which is
here.
As for third party lenses, like Sigma, Tamron and Tokina, some of them will fit. These companies make their lenses in various mounts (Canon and Nikon and then some others as well). The page I've linked to above lists 75 lenses, many of which are third party ones.
They are often very good quality and also, often, more competitively priced than the own brand lenses so don't be put off by the fact that they're not made by Samsung.