Trivia: Sigourney Weaver was not that keen to be in the sequel to Alien, so she demanded an exceptionally high fee considering her fairly low status as a movie actress at the time and also a percentage of the box office takings. The producers were going to drop her and go ahead without her but James Cameron insisted that she was fundamental to the film and so her fee was accepted and paid.
Trivia: Early marketing research ahead of the film's release showed that a significant number of people mistook 'Aliens' for the original movie 'Alien.' To address this, the studio made sure commercials referred to the film as "Aliens: the new movie" and gave the film a logo visually distinct from the one for 'Alien.' To this day, 'Alien' and 'Aliens' are treated almost as separate brands; merchandise and tie-in media tend to evoke one or the other, rarely both.
Answer: The company doesn't wait 57 years, they built a colony on the planet over 20 years prior to finding Ripley. The company was apparently unaware of the exact location of the derelict spacecraft. After finding Ripley and obtaining information from her, Burke was able to send the Jorden family to the precise location of the derelict spacecraft.