Search bar option: only show results of last x months or years

Usually I am frustrated that googleetc are providing me with old results and that I always have to filter them out in a second step. Your wonderful extension yould have a preferences option with
"Search bar opt.: only show results of last x mths, yrs "

then I'd almost exclusively use that.

> Also an option for searching in alternative search engines would be great :)

Search bar option: only show results of last x months or years