I'm not aware of any laptop/notebook that runs 6-12 hours on battery. The only way to do that is to buy $300+ battery packs. Not worth the money to me. You can alway bring the lightweight power adapter with you.http://www.shopping.hp.com/series/category/notebooks/dv7t_series/3/computer_store
Click customize & buy under Base configuration on the right. Add 9600M GPU for $100+. 8400 doesn't cut it for gaming.