I've raised £8000 to Pay for surgery to remove a tumor attached to Rhea’s heart.

I rescued Rhea from a Greek Island some five years ago! She had a really rough life there living off scraps, being shot at, with the lead shot still in her right leg. The shot having broken her leg and as a result of the shooting and she had to let it heal without any care Which must of been very painful.These are only a couple of difficulties little Rhea has had to content with!
Dispite these challenges, Rhea is a very loving dog and she melts the heart of anyone she meets.
I have just been told, she has now got a tumour surrounding 65% of her heart. The tumour is quite large now growing against her windpipe, which is effecting her breathing. Unfortuneatly, she only has a couple of months to live even though you can see she looks healthy.
Rhea is such a fighter and such a character and I am trying to help her in any way? If you meet her, she would make you feel as though you are her favourite human, she is not very loyal on that front...
I am contacting specialist vets to see if there is anything surgically that can be done, but this requires funds.
Any help would be much appriciated.