WiFi mini PCI-e

I am looking for a WiFi card for a notebook with OpenWrt and that can handle 2.4 GHz and 5 GHz simultaneously. There are some? What price?
The use that I will give is occasional when we are at the back of the house eating and the signal arrives.

No, there are none - you'll have to look for two cards, one for each band (and a device/ board that can handle two).

Yes, if you look through the forum for previous questions of this kind, you'll notice that this isn't quite the full truth in theory, but you'll also find in depths explanations there why that's still the case for all practical intents and purposes.