Speaking to the Herald in a hoarse voice, Mrs Patel said: "I was just screaming, yelling, go away, I chased them away with the stick."
A probation officer is understood to have then chased the pair to at an address in nearby Matthews Ave. Police arrested them a short time later. Six other young people were at the house with no adults present, said police.
There, police said they were abused by the other young people, who locked the doors and windows.
The rifle and clothes they had been wearing were found at the house.
The 12-year-old allegedly spat at a police officer, punching him in the face twice and kicking him in the mouth, police said.
Police believe he may have been under the influence of methamphetamine at the time.
Both boys are facing charges of aggravated robbery, while the younger of the pair will also be charged with assaulting and resisting police.
Detective Richard Garton believed the rifle was not loaded at the time and no ammunition was found when the address the teen had been at was searched.
The dairy was closed Monday morning while the victims were speaking to police and evidence was collected from the scene.
Inquiries are also being made into how the boy came to have a firearm.