400? that is very low. No matter what network you choose your payment wont be that high. Maybe when you reach 1000 a day you can start contacting different adnetworks.
Can you try and sell an affiliate product? If the visits are highly targeted this would not be too difficult.
Yes, I had once average of $5 with a blog with traffic of only 1200 monthly .. it was highly targeted.
You can use infolinks its good but u need lot of visitors. You need to increase traffic to your site.
400 is extremely low traffic, but if its good active visitor than you should try pop program, even if you get 100 active visitor, you may earn something, in cpc there is very less chances you may earn anything
To earn from ad-sense then there is required minimum 5000 to 8000 visitors daily then you can get earn $2 to $5 daily. Another option is you can earn money by selling affiliate products. For that there is required quality product in reasonable price with on time delivery.