Want to buy a new Lens for my Nikon D3100

Hi I looking to buy a new lens in 2-3 days , I am beginner I have a default 18-55mm lens which I am using for last 4-5 months. I am looking to upgrade my lens.

Since I don't have much experience I am looking for cheaper and good lens may be sigma

I cam across 2 lenses please suggest which one should I go for or if any other suggestion please let me know. I am currently leaving in Pune

http://www.snapdeal.com/product/NikonAFZoo/59647?pos=0;11

http://www.snapdeal.com/product/sigma-70300456-dg-macro-for/270805?pos=10;11

I am looking for lens for Nature/wildlife photography