virtualenvwrapper.tmpenv should be installed using pip:
$ pip install virtualenvwrapper.tmpenv
You will want to install it into the same Python site-packages area where virtualenvwrapper and virtualenv are located. You may need administrative privileges to do that. Refer to the virtualenvwrapper documentation for configuration instructions for virtualenvwrapper.
Note
virtualenvwrapper.tmpenv is loaded into your shell environment when virtualenvwrapper is initialized. After installing it, you will need to start a new shell or re-source virtualenvwrapper.sh to cause it to be activated for the current shell.