Again, I'm assuming she's American. US citizens are visa-exempt, so she's not getting a visa at all. There are no multi-entry or single-entry visas for Americans. They are permitted to visit without a visa, and they can extend their visitor permit (which is what you've applied to do), but as I mentioned it is nullified when she leaves Canada. I know it's confusing, as CIC uses the term "visitor visa," but it's not actually a visa.
Others have mentioned a visitor record for Americans. I don't really know anything about that.
As for what to do, either continue living together until you qualify as common-law (and a three-week trip during that time is pretty risky), OR get married and apply as married. Those are really the only options.