The Makarov is a superb gun, very accurate, very easy to maintain and equally as easy to load. As stated by others, dies are unique so you can't use a 9mm set. The Maks' bullet diameter is different from the 9mm and if you do try you'll pay an ugly price trying to seat a bullet.
With regards to cases, this is the most frustrating piece of business, keeping track of them on the range and keeping enough on hand. I suggest that you mark your cases; color coding with a sharpie, something, try anything. I don't know if dying a case is possible, but if so, give that a try. They are a precious commodity.
Starline sells new brass. There are not many used brass vendors.
http://www.kensbrass.com/ this guy has Mak brass listed on his site, none available now but it wouldn't hurt to contact him and see when he might be getting more. Else, you are left to cutting brass down.
Good luck. Enjoy the gun.
Be safe.