At the end of the evening, the bar was almost empty, with only [I/?] and a very cheerful and pleasant lady I met in the last minutes of the meeting.

What is the correct form in this case?

My assumption would be to say "I", and also to invert the two subjects, as in the following wrong case, followed by the correct form:

• (*) me and her went to the pub

• she and I went to the pub

If my assumption is correct, I have a different problem. I end up with the phrase:

At the end of the evening, the bar was almost empty, with only a very cheerful and pleasant lady I met in the last minutes of the meeting and I.

As you can see, the need to detail information about the lady pushes the "and I" too far to be reasonably meaningful in the context.