The usual fix for problems like this one is to make sure the version you want is first in the search path of your shell (or the other version isn't in the path - but that's sometimes impossible).
With Unix-like systems, check the value of the $PATH
variable.
[EDIT] See this document for the general concept of wrapper scripts.
Create such a script with this content:
#!/bin/sh
PATH="/Users/Alberto/anaconda/bin:$PATH"
export PATH
exec anaconda
This assumes that the Python which you want to use is in the folder /Users/Alberto/anaconda/bin
and that the program which you want to wrap is called anaconda
.
Make this script executable. After that, you can start the application using the wrapper script and it should always work.
Note: Platypus might make it easier to use the script.