Contact consulate
Send a fax of your application to the consulate with a copy of her passport and birth certificate and marriage certificate with a cover letter explaining the situation and asking them to set up the appointment for your wife also.
Also, call the customer service representative at the consulate and explain the situation to them. I think they will probably advise the same as above (this is what they did for people with similar circumstances previously).
Even if you do not get the appointment letter revised, you might still be able to complete medicals, lab and enter the consulate with your spouse by showing the passport, marriage certificate and birth certificate of your spouse.