I figured it out. Under Products->Settings->Presentation, there is a drop down “Select what product group you want to display on the product page.” I used that to change the product page and changed [wpsc_category=3,full] to the correct category number so that it was [wpsc_category=7,full].
Next problem is how to change the display so that it will display as tiles rather than in a list. I’d rather figure it out for myself than buy it, but it may come to that in the end.