I'd recommend Wix (available as NAPA Gold) for an inexpensive and good filter.... newer Toyota filters are not all that. Last I checked K&N were well above FRAM, more along the lines of Mobile 1... both are over priced for what they are though.
Now that you've got the filter in an easy to reach location why do you need the nut anyway?
I would take the filter mount off and take it into the store with you and simply try a few filters until you find one that fits your needs. I did this when looking for the biggest one I could find.
If you want more information on the more common filters out there read this thread:
http://www.supramania.com/forums/showthread.php?t=42763 (It's on another site and may require you to register.)
If you just want the absolute BEST filter, look at Amsoil EaO and Canton.