Bob,
If you're getting along fine with one body, then I would say go for the lenses--the DFA100 and the 55-300. If you find that you're really missing a second body, then go for another K10 and the 55-300 and save up for the macro. With that, you'll have a greater FL range covered. In the meantime, if you want macro on the cheap, you could always pick up a Raynox macro attachment and use it on either the 55-300 or 200. Remember also, that the 17-70 has quasi-macro capability (1:2.3), which can get you pretty close.
One thing with either macro lens (Pentax or Sigma) is that they're both FF compatible, which means that you can use them on your film body, as well as your digital body.
As much as I like my K20, PMA is so close (next month) that you might consider holding off on buying another body until we all see what Pentax unveils then.
HTH,
Heather