I tend to buy most of my paint on Ebay these days, my local paint shops closed down a few years back and it's a bit of a trip to get to the next one, I only go when I need a special colour match or something.
Try "e-buy-paint-equipment" had plenty off them and always a good service.
For the correct finish you'll need a satin black rather than gloss, although a lot of people use a gloss and polish it up.