I have always been into dream analysis. Some times I get it on the first try, other times I have to ask questions to understand the dream. I have kept a dream diary for a while now.
First off, the old lady is more of a sub-conscious thing than being an old lady. Sometimes you have to think of this as if you were talking to yourself. The mind always just to poke fun at things by showing it in a different light. And many times it uses puns. For example your screwdriver. Getting screwed or screwed over are the first things in my mind when you talked about the screwdriver. It would be interesting to find out if there was a particular place where the old lady was poking you at with the screwdriver. The funny thing is that it happened to you and your wife. I am guess that what ever happened to you and your wife is the same thing and it happened within two days of the dream. So, talk to your wife and ask yourself, how did we get screwed within two days of this dream.
Since the dream didn’t elaborate on what happened. Most the times it does. Mostly in many dreams, in which most you forget during the night. But, anyway, one thing that I should point out again is those damn puns. A pun for old lady is Wife. I know it sounds weird, but it might be. I don’t think the dream was talking about your old lady, but maybe someone else’s old lady or wife. So, that is something to think about. Also, the old lady might represent something your mother might comment on. That is probably why you wife didn’t dream of an old lady, because it would be her mother or might be her mother.
So, I would be interested to see how close I came. If you remember more about the dream or have dreams similar to this please post them here.