There is nothing stupid about buying a plant even if it is only usable for one season or part of the year - I do it all the time.

I know of no Eugenia's that are frost hardy let alone winter hardy. The one that is commonly used for those topiaries is from Australia or SE Asian I believe and more than likely is not gonna enjoy our winters.

They are kinda tough so I would bring it in but keep it near the door - most of them hate our dry indoor environments. Put it back outside when the temps are pleasant during the day.

I took the Eugenia out of the urn today (it has spent the last 2 nights covered with a towel, which obviously I cannot do all winter)and re-potted it for indoors. I had read that they like humidity so it is hanging out in the window with my prized rosemary topiaries which means it will get misted and moisture levels checked daily. Now I have to figure out what to put in my urn, I did have a dwarf Alberta Spruce but I want a topiary of some kind. Thanks!