You will need 135mm between the dropouts to fit IGH. It will probably already have horizontal dropouts, so that's good you won't need a chain tensioner. You will need a new rim and spokes and the skill to lace up a wheel or pay someone else to do it (about $40.00 US). The hub, parts kit, and shifter, sprocket, may or may not need new chainring.
Since you haven't purchased the Uno yet, it will probably be cheaper find a model that comes equipped with the IGH. I think Downtube has a model that is fairly reasonable.