Well, the OP could shop elsewhere if there are other places close by, but if he's stuck with this as the only store nearby, then his options may be limited.
If the woman was young and inexperienced, she may have blurted it out without thinking. It may have been a stupid thing to do, but it may not have been meant to be insensitive. I think the intent is important to consider before deciding how to approach it. The damage is done, it's how to deal with the aftermath.
If she's in retail, she may be young, inexperienced, working part-time and making minimum wage like a lot of other people. It may have been a dumb, really dumb, mistake but not meant to cause harm. If that was the case, and my options were limited as to available stores, I would probably call her out on it the next time I encountered her in the store and let her know why it was insensitive.
If, on the other hand, it was said in such a way that it appeared the intent appeared to demean, or not giving a damn if other people were to hesr it, then, I would get the manager's coordinates and follow up with a written complaint.