The name of the episode Tamara is going to be appearing in is called Murder He Wrote and will air 22 October 2012. A brief summary of the episode goes:

Castle and Beckett deal with an inexperienced police chief and his right-hand man as they investigate the homicide of someone whose testimony sent at least one person to jail for insider trading. The crime-solving twosome strike so much fear in one potential suspect, he dives off his boat and tries to swim to safety!

The episode will air on all ABC stations. Please make sure to check your local listings to be sure not to miss it.