You need to start with a protein treatment to get your hair healthy. These are the ones that come to mind.
1. Joico K-Pac
2. Aphogee two step protein
3. Curl Junkie Repair me

The first two you can get on ground. They work ok but i don't like them because they have mineral oil in them. The curl junkie one you have to order online but it's much simpler to use and it works wonderfully. I usually order through and I get it the next day.
Good luck!
Hair: 3a, normal porosity and elasticity
My hair loves: Vatika and Bhringraj oils, adores henna.
My HGs: Bobeam's shampoo bars, CJAO, CJRM, Original Moxie's Hair Bling, Terressentials,

Let's hear it for beautiful curls!!!