It depends where in Peru you are going. Andy and I were planning a trip to Peru a few years back to visit friends and there are tons of clinics in Lima. Of course, you would have to self-pay but the treatment costs averaged about $100-$150 per session; not too unmanageable. I used to have a link listing all the clinics there and their costs but I'll have to dig it up (it's been a while). I'll post it here for you if I find it and you'd like me to.
Update: Here's a good start:
http://www.globaldialysis.com/Search-for-dialysis-centres-travel.htmlYou do need to register (it's free) but once you do you can search for clinics anywhere in the world. If you click on the clinic name it will give you all the info you need, including the clinic's website, phone number, contact person, etc. It's not the same site I used before but it is a good one.