Here´s another fellow southerner, from Argentina. I understand your problems getting what comes by as everyday stuff for minis players around the globe.
I havent really checked every post since there are many, but I think I get the picture pretty much.
First of all, let me tell you, you have excellent hand for painting, it really shows. Painting with enamels is a pain in the ass, and the reason the minis shown on this and other webpages look so good, is because we use acrylics as some already told you.
I´m pretty sure THERE are some stores in Brazil who sell citadel colours...we have some in Buenos Aires, and since your country is a much bigger market i´d bet on it. The thing is, they are not that really popular, only with Warhammer player, and since you havent played other mini game sas well, that´s the reason.
Effectively, Wayland and maelstrom have been forbidden by GW to sell their products in SA. But they still ship ALL other brands!!! You can get the excellent Vallejo colours, Coat d´arms, Privateer Press colours, ame way you get the Dust line products.
They are definitely cheaper when shipped than bought on a local store (normally double price for being imported stuff), but you have to wait for them on the dowinside!
There´s a fellow wargamer veteran from an argentinian Wargames whom you could contact for getting directions of stores and such...
In the meantime, you can always have what are calles decorative acrylics to use in your minis. You have to water them to use them, but should only cost between 2 or 3 reais each bottle. If you water them enough, they can easily replace washes (not as great as, but pretty good)
Please, let me know if I can be of assistance on anything.