Patella surgery for Sammy the dog

I have for the first time in my life found it necessary to ask others for financial help.

Two months ago I found myself in possession of my brothers dog, Sammy who is a 1 1/2 year old Staffy who until she came to me had never been to see a vet. I took her to see a veterinarian and got all her vaccinations done as well as a general check up, during this visit the vet informed me she had a problem with her knee caps where her patellas luxate (move side to side), but at this time she was still running and walking fine.

He said she will eventually need surgery but over the last month she has got progressively worse where she is completely lame on her back left leg and holds it up all the time, her recent trip to the vet last week is when I found out her muscle is starting to go hollow (this will come back when she starts to walk on it again).

She is being spayed tomorrow (17/4/15) and will have xrays taken at the same time so the vet can see how extensive the problem is.

The cost for everything involved is going to be around $2500 I can cover part of this but I never thought I would have a cost like this so realistically I can not afford the whole amount.

She is a lovely girl and I really want her to have a great life, if she has this surgery while she is still young it will make such a difference to her.

(UPDATE: unless I can get enough funds, Sammy will at this stage only be able to have the deepening of the groove while still a good option leaves the risk for the patella still slipping. the new cost is between 1,256.70-1616.60 for surgery and $50 a session for hydrotherapy)