Just went through this quest. The Collector is a Balance Rank 7 Boss, and has 3800 Health. Magma Men roam around it, and you will usually get one in your battle. Once you get the reins, go to Kimerith Windhammer and press X or left click him. He will give you the next quest from there.
i just finished that quest. the collector will be on the street. press M in your keyboard and follow the map. hope i was a help! katie frostflower,lvl 50 in dragonspyre ps. you might want t bring a friend along... i had to do it 2 times before i finally defeated the collector
fun fact: the collector was originally named the hoarder all of her drops still have the hoarder name on it though!