You should be making at least 1K per month comparing those impressions with mine in saying that site topics differ.
Couple of questions...if you cant answer them here (TOS) feel free to PM me.
What is the site topic if you dont mind me asking?
Is there a general rate you are getting per click? Plus how many clicks?
Take a look at
AdSenseBlackList.com - Filter them and increase your revenue ! and try to weed out any low paying ads.
How many adsense blocks is being used? If you have three, try two and see if there is an improvement in click rate and payout.
Also, what style or colours are you using? I see good improvement using the ads titles as the same colour as the site theme, black text, black url and white background.
I suggested a 160x600 on the left hand-side of your other site, can you try the same on this one?