Baytril is sometimes the proper medication for a RI, and sometimes Amikacin is the proper medication - tests need to be run to find out what the bacteria that THIS snake is carrying will respond to best.
I would not recommend self-medicating without the guidance of an experienced vet (ie, no short cuts)
Dr. Scott Stahl talks at length on Reptile Radio that Baytril is NOT the "cure all" for treating RI's, and if it was, he wouldn't have had to go to vet school for 8 years to learn how to properly treat reptiles. It's a huge pet peeve of his.
If you cannot afford to provide proper medical attention to this animal, I would recommend finding a rescue local to you that CAN.
Here is the episode on Reptile Radio that I recommend people take time to listen to with a lot of great information:
http://www.blogtalkradio.com/reptile...ile-Veterinary