Scott, do a Google search for: Mecion AA contact plates positive to negative.
It will show you exactly what you need. It is a 30 pack but cheaper than a trip to Ballarat where I couldn't find the same thing at Jaycar.
NOW FOR THE CAVEAT. For you to be able to replace the contact plates in your battery case, you MUST be able to lift the plates out with a screwdriver. You pry the old one out and you push the new one in.
If you look at the battery holders at Jaycar you will see that they all appear to be crimped in. You cannot replace the contact plates in this type of battery holder without drilling out the old one, and even then there is no slot to hold the replacement plate in.
Clean the existing battery springs and contacts, then look at the contact for the POSITIVE end of the battery. If there is a hole through it then it is crimped and can't be replaced with those plates. Check out the battery holders at Jaycar and you will see what I mean. Their battery holders have the POSITIVE contact crimped in and the spring for the NEGATIVE is connected to it via a single wire which also makes the spring.
If you need any help I can probably drop in on my way out to Talbot or Maryborough. You won't be able to PM me until you have 10 posts.
Regards Axtyr.