Sine needs much needed surgery

I'm 46 years old and suffer from arthritis in various places. l need a knee replacement asap. I had lapband surgery years ago which did help me lose weight, but then began causing chest and sinus infections so I had to have it deflated. I now need a revision surgery which would convert the lapband to a gastric bypass. This would mean I could reach an appropriate weight to have my knee replacement and enjoy life again. I have half the finance needed but am hoping to raise the other $13,000. Any contributions would be amazing.