My standard starter suggestion applies:
$35-45 iStick/MVP v2+ (MVP as v1, v2, 20w, and now v3 - v2 is 11w, v3 is 30w - 11w is enough to push MOST clearos - will struggle or not fire the new "SubTanks" on the market)
$20-35 Kanger AeroTank / Aspire Nautilus BVC (both have mini versions for a smaller tank)
These batteries I suggest have 2200mAh or more - 650 is lasting you about half a day, so 2200 should last you over a day and a half (3.3x the battery life).
The iSticks are small enough to fit in your palm. THe MVPs are bigger but more durable. Check out youtube reviews and threads on ECF for the full story about each. I dont believe the iStick has step down (delivering less power than the current charge level of your battery), so you want to buy higher ohm coils so you have more control over how hot your vapor is (look up ohms law to understand this concept, but the higher your ohms the less wattage you get assuming the voltage does not change).
The tanks I suggest have air flow control so you can open up or restrict the airflow for your desired hit. Even if you stick with your ET-s the batteries will make it perform better (dunno why, but this is my experience!)