OP, maybe you could try to negotiate say 2-3 hours every other weekday and 1 whole day for Saturday, because 1.5 hours doesn't really give much to complete quest (or gain at least 1 level), also you wont be able to maximize your subscription time.
Try to do chore bargains as the others have suggested. Make the parents impressed by showing them that gaming is not really the priority, just a short term goal.
Trust me, too much gaming could really mess one's priorities (sports practice, dates, family ties, even exercise lol). I just get the 2 hours daily game time as a reward for myself completing tasks in real life.