The woman got up from her chair after 45-year-old Darren Williams opened fire at Carol-Ann's salon in Malpas Road.
His estranged wife Rachel Williams, 37, was shot in the knee. Rebounding shots injured the widow and another customer.
After a six-hour search, armed police found the gunman's body at nearby Brynglas woods on Friday night.
He had opened fire with a double-barrelled shotgun in the salon, intent, according to Gwent Police, on targeting his estranged wife.
Vet Peter Heathcote described how he ran to the salon after hearing gun shots.
Mr Heathcote, who works nearby, said: "I have never seen anything like it. I did not know what I was going in to - whether people had been shot and whether they were still alive."Rachel Williams was lying on the floor and the older lady had blood coming from her head.
"She was very shocked but said she was trying to protect the woman who was shot, which is amazing.
"She had tried to kick over a table towards him and it was still there broken on the floor.
"The old lady was worried about where she had been shot because she didn't want surgeons to shave her hair - because she'd just had it cut.
"Rachel was very calm and I was trying to reassure her as she was laying on the floor.
"She told me how she had been shot in the leg and that it was her ex-husband who had come into the store.Darren Williams was jailed in 2004 for possessing prohibited weapons
"The gun was right there next to me. It was an antique shotgun and looked very elaborate."
Mr Heathcote said his surgery staff helped the wounded women until the ambulance service arrived.
He added: "They did tremendously well, while so many people will run away from this type of scene they ran towards it to help."
The 92-year-old woman, who has not been named, was later released from the Royal Gwent Hospital.'Traumatic break-up'
Mrs Williams was also treated at the hospital, but has since been moved to Morriston Hospital in Swansea.
Police are still investigating how Mr Williams, who was known to have a passion for hunting and outdoor pursuits, obtained the illegally-held shotgun.
He was jailed for four months in 2004 after police discovered what was described as an arsenal of weapons at his home in Newport.
It included a stun gun, a .22 pistol, a machete, a hunting knife, canisters of CS gas and bullets.
Mr Williams' family has told BBC Wales: "Darren has suffered for the last few weeks due to the traumatic break-up of his marriage and desperately needed professional medical attention.
"The people who have been hurt, family and friends, as a family we feel that had Darren been given this help and support the situation could have been avoided."
Police are looking at CCTV images to try to piece together events before the shooting.