Wee's Surgery

Wee is a 6 year old chihuahua mix. She is my best friend and beloved family pet. Recently we had noticed she would no longer climb into bed or onto the sofa when it was time to settle down without me picking her up. 
She was recently taken with me to visit my family in another state in which she would be around my family's 3 small dogs. While the other dogs would play in the yard she was attempting to run but almost hopping in discomfort.  My f amily members were running and calling her name, but she just didn't have the energy she used to. At that point we came to the conclusion that there may have been an issue so I made an appointment with her veterinarian the day after we had come home from my family's, and I was hoping she was just under the weather.  A few days later at her appointment the doctor started to assess her and within seconds she looked uncomfortable. We were told that both of her knee caps were just floating around inside under her skin and that it was causing her a lot of discomfort. We could visually see her knee caps moving when the doctor showed us what was happening. The veterinarian stated as she continues to age and her arthritis gets worse, she will soon become crippled in her hind legs. I've called several veterinarians and all have given me the same advice: surgery before it's too late. I'm currently working day and night to support myself since my separation, so funds have been very tight. Wee has been my best friend through everything, my good and bad days and I would never forgive myself if I didn't find a way to help her. No donation is too small. Please help me help her so she can live her life normally again.