The best place to get beef is from wholesalers.  I use pok brothers, you can buy whole joints a few Kgs at a time.  Just google search for them - they have 2 locations in the Klang Valley.  Last year I got 3.1kg cuberoll/ribeye for about RM225.  And I also picked up wagyu striploin (between 3-4kg) for less than rm800. 

I don't know about buying dry aged steaks because its damned time consuming and unless the butcher is moving enough volume, he's going to waste a lot of meat selling them as individual steaks.  So if you're buying whole joints, then you might want to try dry aging your own beef.  Just need to clear some space out in a fridge.

don't think you can find any dry aged beef off the shelf in Malaysia. unless you got special contacts with the suppliers.
even wet aged is rare. but still possible

Dry aged bone-in ribeye is available from w-mart, sg besi.

recently, grain fed ribeye price is over $120/kg, wahyu eye round is $100/kg, price has increased fair amount. if one know how to cook, eye round texture could become tenderloin like.

those take steak with sauce, whether the steak was grain fed, grass fed, frozen or chill would hardly made any different.