I think it depends on what's important to you in a speaker. As a gross generalization, all things being equal, monitors are going to give you better imaging, and floorstanders are going to provide better bass response. Is one of these more important to you than the other? You also didn't mention your room, as smaller rooms usually do better with the monitors (again, not always 100% true, but works as a generalization).
Since you already have the GR10's, why not invest in used speaker stands. Then, if you have a local dealer that you have a relationship with, see if you can borrow some floorstanders and so you can hear what some of them offer. And if you do decide that you prefer the sound of one of the floorstanders you hear, then you can sell the speakers and the stands to make the funds.
Michael
Since you already have the GR10's, why not invest in used speaker stands. Then, if you have a local dealer that you have a relationship with, see if you can borrow some floorstanders and so you can hear what some of them offer. And if you do decide that you prefer the sound of one of the floorstanders you hear, then you can sell the speakers and the stands to make the funds.
Michael