Much as I like Subarus -- considering the fact that I have 3 of them that's pretty much
-- they're not going to win any fuel efficiency awards.
Stop/go driving is absolute death for fuel efficiency in Subies. Getting all that AWD stuff spinning takes energy and there is no way around it. Other forums I've been on are commonly found with people griping about poor gas mileage in stop/go city driving.
Pump the tires up to sidewall max, try not to stop, and remember all the other great qualities Subarus have.