Best to level up some with some side quests I'd say.
I'm a ranger as well and had trouble with that part at level 10 or 11. I used the high ground a lot and just peaked out enough to get off shots at one guy at a time. Lots of them are archers so they hang back and don't rush in. Take one guy out, move out a little, take a shot or two and duck back into cover to heal or whatever.
