The Welsh Assembly Government said it could not provide funding as treatment was already available on the NHS.
Dr Power said she set up the unit when her home became too small to cope with the increasing numbers of ex-servicemen she was treating.
According to Dr Power, the main difference between Pathways and other units offering treatment is the level of support for the men, both during and after the initial six-week course.
There is also help and support for family members.
She described the process of setting up the charity as "horrendous"
I was going to head to the hills, but after 10 days here I already feel more at ease
Archie McConnell, client
"Without the funding I can't help these people. Bills need to be paid, food, salaries. I've used my money up to now, £130,000, but it is running out," she added.
She said the argument that there was treatment available within the health service did not add up because the unit was getting referrals from health authorities across the UK.
The unit activities manager, Les Standish, served in the Falklands, left the military to work in the prison service, and suffered a breakdown after a riot at Strangeways Prison in Manchester.
He was treated, and is now intent on helping others who are going through the same experience.
"We aim to bring them into a 'family' as we have an idea of what they are going through," he said.
"If you get treatment and are then left alone you can get introverted, and so we offer them different activities which do not involve the TV or a computer game.
"It builds confidence, gets them used to group situations and gives them back their self-esteem. They get fitter and begin to feel better," he added.
One of the men who may have his treatment stopped because of lack of funding is Archie McConnell, from Perth in Scotland, a former soldier with the 1st Battalion Queen's Own Highlanders.
A veteran of Northern Ireland and the first Gulf War, he heard of the centre from a friend.
"It is always more difficult when you go back [to everyday life]. That is the difficult thing, but here I'm learning coping strategies,"
Another client, Thomas Rowlands, from Anglesey, and formerly of 1st Battalion Royal Welch Fusiliers and a veteran of Northern Ireland and Bosnia with the UN peacekeeping force, was told about Pathways by Dr Dafydd Alun Jones.
Dr Jones ran a clinic for sufferers of PTSD at Ty Gwyn, Llandudno, until it closed in 2005 due to lack of funding.
He said he was delighted that a new group had been set up to help former servicemen who could not be helped anywhere else.
Mr Thomas said he could not settle into civilian life after he was given a medical discharge from the army.
"I had 25 jobs, the incentive was there to work. But, driving trucks in the middle of the night, I would get flashbacks to things I'd seen," he said.
Robert Weir, from Edinburgh, Scotland, a soldier who served in Kosovo and Iraq with the Black Watch 1st Battalion, may also have to leave because of lack of financial support.
If none can be secured he said he would consider moving from his home in Scotland to be near the centre, so he can access the treatment.
A Welsh Assembly Government spokesperson said consultants for the company were advised, at the first point of contact with the appraisal team, that the project was not eligible for grant aid because services which the charity provides can be provided by the National Health Service.
"Veterans across Wales have access to mental health services through their GPs and community mental health teams, and where required, specialist in-patient services," the spokesperson added.