Prolapsed Anus Operation for My Little Rescued Cat (Sham)

I had this rescued cat, found her placed inside a plastic bag and thrown away. Unfortunately, her sister didn't make it. And now, my sweet rescued cat has been suffering of rectal prolapsed for almost 2 years now. And she has no control over her bowel movement. Even when she's asleep, she would defecate uncontrollably. I've been planning to have her undergo the operation but it is just too expensive for me. I hope to raise money for her and get her back to normal. She's a really sweet cat.