SO, K-3 and SIgma DC 50-200 4-5.6
Or K-30 and Tamron 70-200 ƒ2.8.
Tough one, I think I'd go with the Tamron, next time you upgrade your body it will still be a great lens. And lately, I've been using my K-5 and K-01 (16 MP) a bit, and they are really quite a adequate for most images. In many case, time spent without an ƒ2.8 lens is time wasted. If you are getting decent results at 200mm 5.6, 200mm at ƒ2.8 will feel like a dream.
For images like this that are cropped, the K-3 has the advantage...
For images where you can actually frame nice and tight, 16 MP is lots. (K-01 image)
I think the big thing here is, both things would help you, the faster more decisive focusing on the K-3 and the wider aperture of the 70-200, so really, you can't go wrong either way.
The 70-200 will be there for the long haul.
The K-3 will make all your lenses better.
It's tough call.