Which lens to buy!!!

[mkgiver]

I have a nikon d80 digital camera with an 18-135mm lens. I am interested in taking very close up photos (rattlesnakes, insects etc.) What is a good lens to buy? I want to keep it under $1000. Should I stick with a nikon lens or are some of the others (tamron) any good? Thanks.

 

[JIP]

Well if your only budget limitation is that you "want to keep it under $1000" I think this http://www.bhphotovideo.com/c/product/424744-USA/Nikon_2160_105mm_f_2_8G_ED_IF_AF_S.html might do just right.