Above garage extension - steel frame required?

CraftBeer

I'm considering a first floor bedroom above my existing garage annex, but the bedroom would be set back from the ground floor front elevation in order to be more visually appealing and less obtrusive looking. See stock image below for an illustration of the set back. I assume to achieve this set back effect, it'd require some kind of steel frame to support the first floor block work at the front face.

Could someone be more specific about the steel work required - would only one steel beam sitting on the walls be required, or a four sided horizontal steel frame, held up with steel columns? Trying to figure out if the cost is worth it vs the usable space gained.

Important to note that i'd be intending to completely demolish the existing garage in order to put proper foundations in, but space is tight so i'd worry that vertical steel columns would look bad in a relatively small space. Garage is typical of the era - very narrow, so looking to also widen it by 130cm and then stick the bedroom on top.

An expensive steel frame just for a 11.5ft wide second living room and a small box room on top seems like it might be hard to justify financially, when I could just build a big kitchen/living area extension on the back of the house instead.