I'm sorry guys, I'm clearly mixed up here.
The NVC has the case, we've submitted all the documents (proof of relationship, I-864, etc) and paid all the fees. The NVC said they will work with the embassy to schedule an interview. I spoke wrong when I said they sent it to the embassy for an interview. And the message we sent was to the NVC, not USCIS. My apologies for all my confusion.
So basically, we just continue to wait, right? The last response from the NVC was in March when they said they will work with the embassy to schedule an interview. So I'm wondering if anybody has a clue about what time frame we might be looking at?