For now you have to lvl till 20 lvl on your own.
If you have a friend who has a high lvl healer you can ask them to power level you on mobs. You need to to be not in a party and healer should put a regen on you while you hit mobs of 15 – 20 lvl with one ranged skill. They will agro on a healer this way (best one is whm who can holy big pack at once). This is a fast way to lvl till 15 lvl.
I have been working on a Sastasha dungeon lately. We plan to add it in the future for people who don’t have squadrons unlocked or for those who want to lvl with bot from 15 lvl. This will take some time though due our current restrictions. On top of that dungeon appeared to be harder to implement that it looked from the beginning. We will have to make the Duty Support as a new feature as well for Sastasha to be working. This will also gonna take time. But eventually it will be added to the bot.