Different armour sets have different ways to get them. Some require Aven Fame and to open up Armour Boxes dropped from Legion Elites. The other is through crafting. Crafting involves gathering materials and handing in a blueprint with the materials to a NPC and trying your luck and seeing if it succeeds.
The level 48 armour set that was suggested is a crafted set and there is sure to be someone in your peer that can make it and if not a world call should get you a reply. Just be mindful that the set might cost quite a bit but on the plus side it's orange grade and has no durability and some passive boosts when multiple pieces of the set are equipped.