If it were me, I would go with the macro lens for the DSLR you already have. You can always update the body at a later time and as long as you got another Nikon you could use your old lenses. They can only squeeze so much into a small P&S body. Most of the P&S cameras out there are a compromise. What I mean by that, is they are good at a lot of things but exceptional at very few. With a DSLR, like you already have, it can be exceptional at most things by just changing the lens. Granted, the lenses can get very expensive.
With that said, P&S cameras do seem to get better every year and the line between DSLR and P&S is no longer black and white, it is varying shades of gray. I have a P&S camera that I bought years ago that I still use, but when I want quality shots I get out my DSLR as my percentage of "keepers" goes up dramatically.
The above is just my opinion and what I would do, I realize not everyone is a camera nut like I am :wave: