In the past episodes the group tried to find new allies for the fight against Negan and the Saviors HUT 17 Coins. They found their way to the scrap yard, but in return they had to surrender part of the "prey", if they were successful. The much more pressing issue is the procurement of weapons. While Negan's people are armed to the teeth, guns, pistols, and ammunition are more of a defect in the inhabitants of Alexandria.
This is why Rick and Michonne are also looking for weapons in the next episode. But Rosita, obviously, is also going to leave, as she does not want to just wait. The Walking Dead: Rosita goes to "Oceanside" In the teaser we have linked below, you can see that Rosita has apparently left alone, To search for weapons.