Salubri

Hello new player here. It seems that even for low dungeons people want at least 1.5k ap. I have BT ring, earing VT neck and badge and aransu 3 weapon and still lacking 200ap for that minimum 1.5kap. Whats the best way to increase AP? What items i should focus first on upgrading or buying?

I saw an old topic in this forum that sacred orbs can be farmed in lair of frozen fang but i guess that doesnt work anymore. What are the best places to farm them today? Cause some crafts need a lot of them.