Just Hit Fifty! Now What?

[Anova]

First, Congrats on 50!

Ishgard only unlocks after you complete the ARR quest line. It's impossible to enter the city without it.

OP can still buy the equipment from marketboards and the like, but it can get expensive. For the time being, refer to this list: xivdb for healing items WHM can use.

You will essentially be obtaining those items from lv.50 dungeons you unlock.

Tomes of Poetry are an endgame currency and earned by unlocking and running optional level 50 dungeons. Here is a list for you to reference, along with the specific quests that unlock them.

Any of the Raids (crystal tower, and coil of bahamut) will give you weapons/armor as well along with tokens, so those should be valuable to you. Prioritize a weapon upgrade (as that will directly increase your healing power). If you have problems with MP, get better armor and accessories. Otherwise, you can probably squeak by with what you have now until the main story quest gives you i115.

As you've seen though, you need to earn Tomes of Poetics (a token currency at endgame) for the high-end gear. Dungeons will give you Tomes of Poetics you can turn in for i120 weapons and armor in Revenant's Toll (Mor Dhona). It's not strictly necessary, as i120 will be good until level 52 (i130 will not be easily replaced until level 55). If you want, save enough poetics for the i120 weapon and that should be good enough.