However during such period of (rental) time I was not a US citizen or resident
You're right. It's complicated. It only makes sense you would not have reported it on a U.S. tax return while it was a rental, since you were not required to file a U.S. tax return during that time. I would "HIGHLY" suggest you seek professional help for the tax year you are reporting the sale. You will need to seek the services of a CPA or other tax professional that is familiar with U.S. tax treaties between the U.S. and whatever country the property is in, as well as the country you are from. I seriously doubt the TurboTax software will be capable of handling your situation.
