Chispa's amputation

Thank you for taking the time to read this.  My family rescued Chispa in 2009.  She has always been a very healthy, playful, silly dog despite her anxiety from unfortunate abuse from her previous owner.  About couple weeks ago she began limping, but because of her playfulness and good appetite we thought it was a simple sprain.  A couple days ago we took her into vet and were shocked to find out the bone on her back right leg is deteriorating due to a tumor/bone cancer.  We had bloodwork, xrays and ultrasound done and there are no other signs of tumors or cancer.  The Oncologist states that her pain is coming from her leg and if amputated she will have a better quality of life.  Although this information has been devastating, her personality has been the same, so our family also believes that amputation is the best route.  Our family is doing the best we can to come up with the funds but are having a very difficult time doing so and feel horribly because we want to give our baby treatment asap.  We will be creating a Facebook dedicated to Chispa's journey to a healthy recovery.  We appreciate any help and are so incredibly grateful.  Thank you.  Many blessings.