Well how about giving say, 20 Rep every time you kill an elite and 50 Rep every time you kill a boss. I don't know the minimum/maximum and points given by reputation heart, so based on that these values can be changed.
Elite level 01-10 - 10 Reputation
Elite level 10-20 - 20 Reputation
Elite level 20-30 - 30 Reputation
Elite level 30-40 - 40 Reputation
Elite level 40-50 - 50 Reputation
Elite level 50-60 - 60 Reputation
Elite level 60-70 - 70 Reputation
For Boss kills put a multiplier value and give that much reputation points. Seriously if you are going to get reputation by killing mobs why restrict it to one map, in this case Tunnel