Only listings that have been submitted to Trulia manually can be edited at this time. We receive your listing information, not from your MLS, but rather directly from Keller Williams and they still show the old price on their site as you'll see if you access the link below of the link to 'View more detials' from the property details page on our site.
In this case you'll want to contact Keller Williams to ensure that they update the price for this listing on their site and within the data feed they send to us. Once they update their data feed, our display should update automatically with the new information.
Please let us know if you have any other questions.