Not function, Addons are generally stored in lua tables (or whatever it's called), every function it contains, every data etc.
You just need to know exact "map" of data to access it also if data is "local" you cannot access it from outside and as i see Auctionator keeps everything local.
Imho best way would be to mail creator of Auctionator to ask if its possible and how to retrieve data from it, other way would be to search/ask on WoW Addons related forums (don't mention you need it for bot ofc ;D ), it's 100% addon-side related and has nothing to do with bot.