You can run a My Finds PQ to get a listing of all caches you've ever found. I can't think of a way to just get your found caches for a specified time period.
I'm not 100% certain that this will work, but try this: go to your PQ page, create a new one. Then when you get to the box that says "and include" choose the boxes "caches I've found" and "found within the last seven days". That should give you a list of all the caches you've found in the past week. If you're looking to make this a custom time period, then I don't know what to do. Hope this works.
The obvious problem for such a PQ would be that it would exclude anything archived since you found. I grant that is low chance but it does happen.
It works to get a listing for the last week. Would be nice if it was possible to give a time period.
andyand