I need a software for statistics, so it should make plots, fitting curves on points, calculate the uncertainty of measurement etc. Which software do you recommend?
Try R - http://www.r-project.org/ For a more general purpose application, and depending upon the level of stats you wish to get into, then there are many potentially suitable applications such as Mathcad (the one I use preferentially), Mathlab, Mathematica, Maple or even Excel \ Open Office. Or, keeping with the single letter choice from the alphabet soup of programming language name, try J - http://www.jsoftware.com/ a very powerful and concise(!) vector programming language.
You mean, other than the 2 big dogs in the block? SPSS and SAS. These two are good, fully documented, supported and expensive. Then there is R. Then, there are programming languages where you do the work and possibly statistical toolboxes like a combination of python, scipy.stats and matplotlib.
I would try R if I were you. It's totally free and is quite popular. Other statistics software can get quite expensive.