[Autumn]

The extenders are an idea I probably ought to think about. Looks like those are something I'll find in a crafts store? I'd need black, nude, and white. The particular one you linked only comes in nude and white.

Would I find them in, say, Michael's? Or Hobby Lobby? Or shoot, the crafts department of Wal-Mart?

My guess is that you'd probably find them in stores that sell sewing supplies (like Joann's) or that have a sewing supplies department (even though I presume that no sewing is required and they just hook on to your existing bra hooks - I've never actually used an extender myself but heard about them from other women). Also, stores they sell bras may have them. They can also be purchased through Amazon.