You can use the same Raspberry Pi that is controlling your sprinklers for the mobile app. Just SSH into the Pi, install a web server (ex. Apache), and clone the files into web directory.
Those are the two steps you need to perform and are detailed in the Github install instructions (https://github.com/salbahra/OpenSprinkler-Controller).
Let me know if this helps.
Update: I noticed you specifically said OS 2.0. Do you mean you have an OSPi setup working and now you are trying to get an OpenSprinkler 2.0 (not the Raspberry Pi model) with logging using my app? If so, just install a web server on your Windows machine (IIS, Apache, etc.), install PHP, and clone my files to the web root.