According to the script for this episode, the pronunciation for Davlos was "DAV-los". 
According to the Star Trek: Star Charts (pgs. 62-63) the Davlos system was located in or near Federation space, in the Beta Quadrant. This system, also known as Nu Tauri, was a single star system. Primary was a Class A star with a magnitude of +3, which was ten times brighter than Sol.