Yeeha or Xiaobaitu: drive to Canada using H1B extensive approval

I am planning to drive to Canada for a short visit. My original I-94 (the small white paper) already expired. I applied H1B extension and it's approved with two I-94 cards attached to the lower half of the approval letter (the number is same as original I-94 card). Can I drive back US using the H1B extensive approval letter with the attached I-94 card, or do I still need to get another visa from USA embassy at Toronto?