Even if you could invite her over for a visit by phone, she would arrive in town as a tourist Mini-Sim -- that is, a scaled down data representation of her real self. Getting a mini-sim to move in permanently while they are still in the tourist state will often if not always damage the sim and quite possibly corrupt the game, while the real version of herself might still well be at Uni.
Without mods, the best you can do is return to Uni (or send another sim), try to befriend and ask her to move in from that end so that she will return home as part of that sim's household.
With mods, you could use NRaas MasterController's Add Sim function to safely add her (the full version of her, not the Mini-Sim) to your own sim's household, to another existing one, or to a currently unoccupied house, thus giving her a household of her own.
NRaas > MC > Add Sim > Homeworld > (filter to Uni World)