I know you asked your question in 2009, but I would like to answer the question since I found the the answer and this community is still developing.
The subdivision for the Hallmark Oak is The Cove at Todville located in Seabrook, TX. Beazer Homes is still building new homes in that community.
I don't know why the listing states that it is located in League City. It is located in Seabrook with the zip code 77586