Many paint shops will do small custom paint matching (Sherwin Williams here in Canada) but I would just look for a similar color in a rattle can. Many modern spray can type paints for metal come ‘self priming’ but if you have a lot of old rust on the metal, you have to neutralize (convert) the rust. I would recommend Ospho (follow the directions, it basically converts active rust over to a stable compound). For any project that is going to be exposed to damp (workshop/garage) I would definitely not skip that.
Preparation is 90% of any paint job, so preparing and cleaning the surfaces (and masking what you don’t want to paint) is what takes up most of the time and what determines the success of the process. The tommy bar is going to turn brown with use, even if you polish it. Both of mine are brown after decades of use. I would just clean and wax it.