What brand of curry powder and where I can I buy it?

If you can find it, Baba's is a Malaysian brand, since this a Malaysian dish. You can probably try S&B curry powder too (though, it's Japanese).

Depends on where you live and the combination of bricks-and-mortar and online merchants available to you.
If there is a good store which has fresh spices and lots of turnover, ask them for a recommendation and sample a few to find out which you like best.
Or, go to an online merchant (a big general merchant or a specialty spice merchant) and do the same with them.
In either case, buy a small jar or package, so you have a chance of using the blend while fresh and pungent (about a year).
On the other hand, if you want the freshest curry powder, and one you can vary as your tastes or recipes change, buy mostly whole spices and grind/blend them as needed. Many recipes out there - from different authors and countries (e.g, subcontinent, Malaysia, Japan).
The only spice you need to buy ground is turmeric, which is very hard (physically) to grind at home.
For grinding, you can use a blender, an electric coffee mill or a mortar and pestle.
Last tip, you could buy or make a curry paste and use that instead of powder. Again, many merchants carry these. I haven't tried all, but in practice I've liked Patak's.