Connie Evans was injured at Carol-Ann's salon in Malpas Road, when Darren Williams targeted his estranged wife on Friday.
Mrs Evans, who suffered 13 gunshot wounds, said although she had been frightened, she did not panic.
Another customer was injured by rebounding. The gunman's estranged wife is still in hospital.
Rachel Williams, 37, is being treated at Swansea's Morriston Hospital after being shot in the leg with a double-barrelled shotgun.
Moments after the attack began, two elderly customers with towels around their heads were seen running from the shop and shouting for help.The incident sparked a major search involving armed police and a helicopter.
Mr Williams, 45, was found dead in Brynglas woods six hours later
Mrs Evans, a great-grandmother, was treated in the Royal Gwent Hospital, but is still suffering from her injuries.
She told BBC Wales what happened.
"This big man came in and I said to myself 'He never wants his hair cut, surely?'
"With that he grabbed Rachel and he said 'I love you Rachel...don't take this".
'So sharp'The shooting at the salon sparked a six-hour search for the gunman
As the gunman opened fire, Mrs Evans fell to the ground, hitting her head on a table.
Although she was frightened, she said she "wasn't crying and didn't get panicky" during the ordeal.
"I was very brave," she said.
Thirteen gun shot pellets were later removed from Mrs Evans' body.
"It was so sharp," she said. "And then my head started bleeding all over my clothes."
After the shooting, the hair salon was sealed off while a forensic science team began an investigation.
The Independent Police Complaints Commission is examining the events leading up to Mr Williams' death.
It has emerged Mr Williams 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.
An inquest is expected to be opened into Mr Williams' death on Thursday.
His 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."