How does Spider-Man know which floor the baby is on?

When Spider-Man swings toward the burning building, the mother on the ground calls to him to save her baby. He immediately goes into the right window to do so. How does he know which one it is? If the answer is spider sense, then that contradicts Spider-Man not realizing that the screaming woman inside the building is actually Green Goblin, and being unable to instantly find 'her'. Speaking of the mother, her demonstration is extremely weak and unrealistic. She doesn't cry or even yell hysterically despite the fact that her child is about to die. The woman looks and sounds more as though she is begging someone to retrieve an important document.