This study will compare lapatinib and trastuzumab. One group of people will take lapatinib and another group will take trastuzumab. The effects of the drugs, both good and bad, will be compared. This study will compare two different durations of HER2 treatment to see if earlier introduction of HER2 treatment is beneficial. The lapatinib group will receive HER2 treatment from the very beginning for 24 weeks prior to surgery and the trastuzumab group will only receive HER2 therapy for 12 weeks prior to surgery.