It is good that they painted it with cheap emulsion paint. For a new house, the dampness of the wall is still there and it'll taken around 24 months to dry up completely. The dampness cannot be seen using your bare eyes and you can only know that if the wall is damp with a device called protimeter. The reason why I said it is good is because the cheap emulsion paint has a lot of powder as you said it is chalky. And the damp wall can be dried up faster when you applied emulsion paint on it. For the powder to be absorbed.

Some people who might have a little knowledge about paint would suggest you to apply sealer, be it the solvent-based sealer or the water-based sealer. Like what blasto said above about the ACE Hardware. They hired sales person who are not so familiar with paints and they might just know which color is nice and which one isn't. People who knows about paint(with experience) will know that what I said above is right.
However, you might still opt for the premium matt emulsion(Pentalite for Dulux, Strax for Jotun and etc.) which has less gum than premium shining interior paint(Pearl Glo, Satin Silk, Majestic Pearl Silk). If you apply those shining paint, then you wall will most likely have something like water mark or damp mark due to its dampness. This is because the gum blocks the wall from being dried up. The same goes to sealer. If you apply sealer, the wall most likely won't dried up so fast or dry up later than usual.

Ok, if you want to change the colors, the cheap emulsion still have plenty of colors for you to choose.

If you want expensive paint, like what I mentioned above, you can still opt for the premium matt finishes.

My recommendation,

Cheap paint:
- JOTUN Jotaplast
- KCC Koreton Plus
- Pacific Newlite
- Sissons Masonry

Expensive Paint
- JOTUN Strax Matt
- KCC Koreton Ezy Clean
- Sissons Super Siscolux

Try not to choose ICI Dulux for it is overpriced and the quality has gone down since a few years ago.
And also try not to choose Nippon Paint for their quality is even worse than ICI Dulux and what I can say is the one of the worst paint is Nippon Paint.

Sorry for if I offenced some of you.

Feel free to ask me more.

what a sunday .... some pictures for all...

so far this is my favrouite roller (recycle but performance best) got for rm5 each.
The green (2nd color) 1st coat.
this is how i keep my tools. jk

my workmanship lagi teruk...
your door overlapping paint or uneven paint or dripping paint ?
can you update us with a picture of the door ?
(i think with picture, pros here can advise better)

spraying... you need a very powerfull compressor... the paint is very thick. 

Yes..
FYI, for Jotun, there's no more ready-made 5Ltr paint with colors...Even the standard colors you find on the catalog have to be mixed with the multicolor machine and price depends on the color...