Seats DO get converted to "R" as departure approaches if they aren't sold for cash. However, this often happens within the EUA window and whatever available R there is gets "eaten up" quickly by the free elite upgrades. As suggested, your best bet for your gf is to waitlist her for an upgrade using your regional upgrades -- you should be able to split the PNR online (I think it's called "separate traveler(s)" or something like that, I don't have any current 2-pax reservations to verify) and then I think you can put in for the waitlist with the RU online as well.

Once she's waitlisted, she should be cleared as soon as the "R" inventory is released, ahead of any elites on EUA (including yourself).