According to this answer
First uninstall python3
brew uninstall python3
Download this formula
https://gist.github.com/booleangate/8f0bb23fdd53d699f763f0959c506049
Then go to directory where formula was downloaded and intro into terminal
brew install --debug python33.rb
From now on, if you want run this version of python you must type on terminal:
07:03:17 $ python3.3 
Python 3.3.6 (default, Jan 26 2016, 06:48:22) 
[GCC 4.2.1 Compatible Apple LLVM 7.0.0 (clang-700.0.72)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> 2+2                 
4
>>> 3*3==9
True
>>> 
Enjoy!