I don't have a spare set but I would recommend getting a set of genuine Fiat mk1 or mk2 alloys. These look better than pretty much all aftermarket wheels out there and will fit perfectly every time. 185/55 R14 is the tyre size used on the Sportings and GT, so this is guaranteed to clear the arches and maintain an accurate speedometer reading.
Moving from steel wheels you will need new bolts with the 60 degree cone seat, which you should be able to get from richie.guy If you need locking wheelnuts, I think it is McGard 29170 that you need - the Halfords guide will have you buying 28169, which have too long a shank length which catches on the rear shoes.