Technically, a REALTOR is supposed to only be a negotiator between the buyer and the seller. DO NOT tell the REALTOR anything you do not want the seller's to know. They should be bound by confidentiality to not share anything between the two of you during the deal, but in my experience, REALTORS talk more than listen.
Saying that, I don't think you necessarily need another agent, just know what you are getting into and make sure you do your research because the agent can only give their advice. Good luck!