You can get great macro shots with the Nikon 60mm Macro, the Sigma, 105mm, 150mm, 180mm, Tamron 90mm etc. There are 100's of lenses that'll do the job. How deep is your wallet?
One thing I've noticed about photography... it costs a lot of money. Need a tripod? $1000. Need a new lens? $800. New camera? $1000. Bag? $120. Memory? $60. UV filter? $99. You're going to use that lens for what? No no, you need a (fill in the blank) $600-1500. It's silly and endless. Get good with what you have and then think about upgrading.