When is a good time to buy airline tickets for April 2009?

My husband and I are planning a family vacation for April 11th-18th of next year. When will it be a good time to buy airline tickets for us and our 10 & 11 year old? I was trying to do some research for next year but due to the dates that are a year apart the search engine was unable to help me. I did do a search as if I was going in May (2008) and I found some flights for $201.00. We will be traveling from LGA to MIA and drive to Orlando, so we will be departing from MCO to go to LGA. Please Help, This is going to be 1st vacation\family reunion. Thank you!