That's very niche. If you like talking to people, you may bring it to a shop that paints cars. The BMW tuning kind of body shop. They may be able to help you on the spot. The bigger shops typically have a paint system where they can mix paint.
If you want to try your luck online, Angelus paint sells little pots and is highly regarded, they also sell various top coats, hardeners and what not.
The ghettoest version, but it could work, could be to buy a spray can from a DIY shop that may happen to be the same colour, and you'd spray that in a container, or mask around the frame and do a bunch of light coats. If you mask, mask extensively (you'd be spending 10x longer masking than painting).
In principle, the paint itself matters less than the top coat you will use.
If you sand back to carbon, depending on the colour, bear in mind you should use a primer first. But if it's a small area, in principle if you just do coat after coat you should end up with good coverage. A can of primer can cost 5-10 eur in a DIY shop.
I ghetto painted a VB frame, restrosepctively, i feel i should have ordered it black and just used car vinyl decals. I would have made my life easier.