Your best bet would be to add the QR number to your booking, which will then show on the BP allowing you to gain entry to the lounge. Once you have entered, you can then head to a service desk and switch the number to your QF number to earn to your QF account instead.
Note that if doing this you may be told you are not allowed access after switching the numbers, and when that happens you should probably have a link to the two AFF articles where Qantas staff members said this and later got lambasted for the incorrect information.
A Oneworld Emerald frequent flyer was incorrectly refused Qantas Club access for a second time in a row.
www.australianfrequentflyer.com.au
Side note to more informed members, presumably if you knew a TA they could add one number to the FQTV and the other...