Sorry, I'm getting back to this just now. Let me discuss this in a bit more detail as the instructions don't seem to have gotten you to where you need to be.
There are two drop-down menus on the top right of qtrGUI. One is the "Name" dropdown which is the printer selection (in this case it's just your printer that you've added in control panel).
The second drop-down menu is basically just pointing to a curve folder (in your case it will be C:\Program Files\QuadToneRIP\QuadTone\Quad4800-K7)
Delete all the files in C:\Program Files\QuadToneRIP\QuadTone\Quad4800-K7 and replace them with the pro curves from >Piezography>Curves>4800-7800-9800-Pro
Restart qtrGUI and you will see them all there.