The problem with Oak Park Real Estate agents is that they are very protective and they don't like outside agents. Even someone like Lorne Frank of Sotherbys who lives in Oak Park but works in Chicago is seen as an outsider. You are lucky to be the buyer, not the seller in Oak Park. You shouldn't have any difficulty working with YOUR chosen Buyers agent. You need to find someone with NEGOTIATING skills.
Here are my recommendations of who to interview:
Pat McGowan, Baird & Warner, 708-445-9090
Lorne Frank, Sotheby's, 312-520-2823
Linda McCroy & AJ Chandler, Coldwell Banker Sprafka, 708-383-8700
Patti Pereyra, a Top Voice here on Trulia, Keller Williams, 773.769.2500
Sorry I couldn't resist, I'd actually talk to friends, neighbors, co-workers for suggestions then call and sit down and interview them. We actually try to be very approachable.
Hope that helps,