You have every right to be upset. Saturn hyped up the greenline, and your experiences aren't uncommon. You can get decent mileage out of the VUE, but it realy isn't the technology that is giving it to you.
Pump up those tires, accelerate slowly from a start and you might be able to get the BAS system to help a little.
Lots of us have higher hopes for GMs 2mode hybrid system if it ever comes out.
One of the other moderators here gave his impression in this link
Saturn Vue greenline hybrid first impression over at cleanmpg.com.