I work at that illustrious institution...So...
She should join the JCU dive club. They run a number of trips every semester on a private charter boat for liveaboard trips out to the GBR and Yongala. The dive club can provide any additional training she may need to dive the Yongala as well (due to depth, they require you to do the deep dive part of the Advanced Open Water if you've not already got it).
Secondly...the local dive shops? I have not had particularly good experiences with either of them. Remote Area Dive runs day or overnight camping trips up to Pelorus and Orpheus Islands a couple of hours drive north of Townsville. My experience with that trip leaves much to be desired. They have also screwed me around multiple times with gear repairs. Adrenalin Dive is the only other dive op in Townsville. They have a day trip boat which alternately goes to the GBR or the Yongala depending on which day of the week it is. These trips are regularly cancelled due to passenger numbers and weather conditions. They are very unreliable as an operator in this context, which is why I don't recommend them unless you're a local and have a lot of time up your sleeve to account for 6 weeks straight of cancelled Yongala trips. They also contract the private charter boat on an ad hoc basis for combo GBR/Yongala liveaboard trips (JCU runs it cheaper though).
As it's difficult to get by around here without a car (though not impossible), most of us would drive ourselves down to Alva Beach and head out to the Yongala with Yongala Dive. Admittedly it's a 2 hour drive south of Townsville, but it's a well run dive op and they rarely cancel trips.
There aren't really any dive sites in Townsville itself. The military owns most of the land around here, so access is problematic. There's a couple of dive sites on Magnetic Island (a 20'ish minute ferry ride from town) if you have your own gear. You can get tank fills over there if you go for the weekend though.
