Follow Teacher 8's suggestion.

Please just follow Teacher 8's suggestion and go to CBP. DOn't go back to China and try your luck.  Tell them exactly what teacher 8 told you. I visited CBP once and the officer is very nice. She fixed my I-94 in 5 mintues. Don't say it's your fault and just say you did not realize the customer officer gave you much shorter time on your I-94 than your spouse's H1 valid time.(Exactly as teacher 8 said). Before you go there, you'd better call them to make sure what documents you should prepare and CBP's local location. Normal it is near airport but not in airport. That's my experience. Good luck.