Urgent Appeal for Chance Boxer

Chance is a 12 year old boxer. He has a very, very bad infection in his toes. I just thought it would be simple to get rid of but it wasn't! It was in fact 3 separate infections caused by 3 separate bacteria, ALL resistant to the 1st and 2nd antibiotics he was given! After taking my boy to the ER on the 18th of October, a culture showed that there was one antibiotic that would get rid of 2 of the resistant bacteria but was very expensive. The 3rd bacteria was a very, very bad staph infection, resistant to most antibiotics. The only two antibiotics that might help was an injection he would have to have daily into his muscle for one month (or maybe more) and they said it was very painful! The other was a very strong antibiotic that could cause severe side-effects and he would have to be closely monitored! All his blood work had to check out to even start it! Well, today he is starting it and he has to have 4 tablets, every 8 hours for at least a month or more which requires weekly or bi-weekly appointments which require lab work, sedation and blood draws.  
This staph infection is deadly if not resolved! So this has to happen or I will lose him!
I am on a fixed income and really need help right now or I'm scared I won't be able to continue with his medical care! The medical bills already are over $2,500! And his medical care will be continuing for a long time! 
I lost my husband, and two of my other boxers in the last 2 years and I'm so scared for Chance! I almost lost him last year when a tumor burst in his spleen and he had to have an emergency splenectomy! He's been with me for over 10 years and he's my absolute shadow! We are so close! He means the world to me! That's why I'm asking for help! If something happens to him and I can't help him I just can't live with myself! He is such a beautiful white boxer, and I love him so much!
And please, if you can't donate for my sweet boy Chance, please pray for him that this antibiotic works and he recovers. Thank you for your consideration in helping my boy Chance!