She said that she would come to see us. So we had been waiting for her since then.

That's pretty close! I would say it sounds more natural to say "there were two of us" - leave out the "the". It would also sound more natural (especially since this is out of context) to include her name - i.e. "There were two of us except for Dianne." If you can make the time more specific (like this: "we had been waiting for her since morning") I personally think that would sound a bit better, however there's nothing wrong with the second sentence grammatically. I hope that helps.

Thanks so much for answering my question!!

There are two of us excluding her. She said earlier that she would come to see us, and so we are waiting for her.