OH NO! Looks like Perianal Fistula! What do I do?

Ok, so after months of medication and vet visits, after buying 105$ cephalexin two days ago to treat a possible infection, it looks like perianal fistula is finally showing its ugly face. You can see all of the drama I already been through to finally figure out what the problem is here(http://www.germanshepherds.com/forum/health-issues/144966-need-help-going-crazy-4.html).

Today I must have creid for a couple hours at work cause I thought my dogs tissue around his neck was really stiff so I originally went back from lunch thinking he had cancer (who knows maybe God loves us so much that he has that too!) but when I cam home to run him for a bike ride, during washing his feet I noticed what looks to be the beginning of a open wound RIGHT on the corner of his anus. So I am pretty sure it is perianal fistula which I have been praying it wasn't for the longest time. Needless to say now I have to go back to the vet, discard 6 weeks, and 105$ worth of cephalexin, only to probably get cyclosporine (for another 100) and god knows what else.

Please give me all of your treatment options for perianal fistula. I want to go to the vet with lots of information, even though she was technically right from the 2nd set of steroids, that if it didn't clear up, it was probably perianal fistula and he would need medication @ 200 a month for the remainder of his life. Any help would be greatly appreciated.