Corinne Barber, 41, was worried she would not be able to make the trip possible due to her large medical insurance bill, costing around £5,000.
Her heart condition, congenital heart disorder, also means that she is not able to fly to Italy, but must instead take a trip via boat, rail and road, according to Edinburgh Evening News.
Her brother, Darren Barber, from North Berwick, set up a fundraising campaign so that she would be able to make the journey.
Donations have come from as far as Argentina and the gaming community has donated too after hearing her story.
Corinne, from Leith, has around £3000 of the £14,500 needed to make the journey to the home of the Catholic church in Italy.
"I need to swallow my pride and ask for your help to make this wish come true.
"When I die I have to leave the man I love behind but I don't want to go without seeing the most holy site," she said.
Mr Barber, her brother, launched the campaign online: "Though devastated by the news, both Corinne and her husband Andrew have faced this with their trademark humour and unshakable faith.
"Corinne has expressed a desire to visit the Vatican before it's too late as her faith is a strong focus for her - and for Andrew."
He added: "I wanted more than anything to be able to make this happen, but the family simply didn't have the means so we decided to set up a GoFundMe page to help.
"It's Corinne's 42nd birthday next week and this would be the best present we could ever imagine giving her."
Her family were told she has between five and 12 months to live.
Her brother said: "Both Corinne and Andrew took a great deal of persuading to allow me to pursue this avenue of help as they are private and unassuming people who dislike attention.
"However, we have convinced them that this is the only way for Corinne to achieve her final wish.
"There is no official deadline for the campaign but there are time constraints because of her deteriorating condition which is creating a quiet sense of urgency."
