You can split the record so you get your normal GM upgrade priority. You can then also request a companion upgrade since she is traveling on the same flight, and have her added to the upgrade list. You'll clear at 3 days (if available) and she won't clear until 12hrs before. You don't need to be on the same record to get her on the list, just the same flights.

If you stay together you'll be dragged down and neither of you will clear until 12hrs, if there is any space.

Note however, if you do split then only you will be eligible for skypriority benefits (EC seats, early boarding, free bag etc).

She would not be eligible for an upgrade on pay with miles. Doesn't hurt to ask the GA if there is an open seat after everyone else is cleared, but its unlikely.