I just received my K1 from QRE, Unfortunately, I completed my 2012 tax return without including QRE's K1. My understanding is that if the UBTI is less than $1000, I don't really need to file the K1 - I understand I'm not taking advantage of the loss, which is only -$63 (UBTI). Is my understanding correct?
This makes no sense. You state you already completed your 2012 tax return, then you talk about UBTI which is only relevant for an IRA. So you are saying you did a tax return for your IRA?
a) If it is an IRA and you have negative UBTI then there is no action needed (you don't get to take a loss as you imply).
b) If it is in a taxable account then you absolutely need to include the K-1 data. Not reporting it is no different than not reporting W-2 wages or 1099-INT interest.
"Sorry, I am an Italian citizen and I live in Italy, I have QRE stocks, can you explain me please if I have some obligations or tax benefits, and if I need to register K1 from QRE. Many thanks"
If you are not a US resident, you should have already had taxes (around 35%) withheld from your distribution payments. If you want to get that amount back then you would need to file a US tax return. You are not obligated to do so, however that is the only way to get back the tax you already paid.