Okay, so to get the quest, I have to be lvl 53? Or can I get it at lvl 45-50 and get boosted through the quest?

It wasnt so hard, priest shackles undeads and shamans use tremor totems like i did. We even killed eranikus and highest lvl in group was 54 (warrior).

The quest is not very easy. First, you have to kill 5 or 6 named mobs that are standing on balconies above the main temple arena. They fall easy, but to get to them, you need to take down a number of patrols that are all around 48-50 elites and lvl 47 imps.

Once you take them all out, you will see a message saying "The shield is down", at which point you go down to the arena level, and have to kill 3 groups of dragons to get to where Jammal'an is, thru a wide corridor on the east side of the arena. Each group has 2 or 3 lvl 52+elite dragonkin, with 4 or 5 lvl50 little dragons.

Once you pass these three groups, you will get to Jammal's chamber, where there are 5 or 6 groups of undead trolls, that can fear you. Safest approach is to have someone pull one group at a time all the way to the back of the hall, so if any of your party members is feared, he won't run into the rest of the mobs and aggro everyone else.
Also, when killed, some of them release a elite spirit that moves very slowly and attacks you. You cannot kill them. Just walk away from the spirits and they'll fade away, otherwise you can keep hitting them over and over and they won't go away at all.

Once you clean all the groups, all that's left is Jammal'an and one other named mob. Have the main tank keep Jammal'an busy, take out the second guy, and concentrate on Jammal'an once you're done.

Hope this helps.