Hey Shinra, welcome back to the game
I currently have a epic (purple) set that was given to me when i reached 80.
However, i'm not sure how do you upgrade that equipment, or should it be upgraded or replaced?
In the end, you will have to upgrade it, but for now, that being from legendary to fable. You have epic because you got it for free fromt he box. You can farm legenary gear by farming the spawning boxes (Antique chests) every 30mins in Al Rihat, or by doing s4's ( They require no keys, but I'd recommend Al Rihat - time efficiency).
Once you have these legendary grade items, you can upgrade them to fabled with the fabled gear reinforcement scroll, that you find on the forge.
You can find more information about gearing here.
Looking at Anvil of Artifacts I see only options to create new gear of the next quality, and just armor at that I don't see weapons.
Weapons are dropped in s5's or crafted by profession: Weaponsmithing.
Also I saw that you can buy equipment in Al Rihat, however I've troubles even killing 1 mob so questing there for the gear is turning out to be frustrating.
Try asking people to go with you, aoe works very nice. I personally feel killing mobs on p2p servr way easier. Which server do you play on? Are your stats setup right?
And what about Astral? can you get gear there?
Yes gear drops in astral, but only about half of everything you can equip.