Read more at Suite101: Two Reasons Home Buyers Should Always Hire Their Own Realtor http://buyingsellingahome.suite101.com/article.cfm/two-reaso
Your agent has been working with you for nearly a year.
You should ask your Agent to get in touch with you to get you the best deal
as well as the best Inspections to help you reduce the price further.
Your encounter with a second agent is not that uncommon. Many buyers attend open house activities in an effort to familiarize themselves with neighborhoods, home availability, and pricing.
Under these circumstances it is always advisable to inform the agent hosting the open house that you are currently working with a real estate agent. Most agents will respect this disclosure and not push the issue.
Your situation is very similar but ....you did not disclose your relationship with another agent. We would hope that provided with this information, the new agent would be able to make the right decision.
Our advice........time to play your cards and see how things work out.