I'm not really digging the center column/center of that pediment. But that just me thinking about classical architecture. Most of the time you'll have an even number of columns to to create a center and a definite point of entry. it'd be cool if you could add some sculptural detail in the tympanum (that blank triangular space above the horizontal and below the roof structure). Here's a bit of reference.
http://en.wikipedia.org/wiki/Pediment looking really good so far, keep at it and turn this into a full blown map.