Well, to conduct a online survey the survey needs to be online.
This means, as long as your computer is not accesible via the internet (which I hope it is not!) you will need to install Limesurvey on a webserver accessible via the internet.
What you have installed is a test or development environment on your local machine. Many use this to develop the questionnaire on their own computer, where they do not have any problems with internet connection or can work offline.
However, if you don't want people just to fill it out on your computer, you will have to have your survey published on a webserver.
Often universities already have a installation. However, if you don't have a huge number of simultaneous interviews, a simple webspace (with PHP and Mysql support) should do the trick.