Your objective in this hand is to stack AJ/KJ That means you need to build a big pot, preferably before the river (to avoid suckouts). If you want to win a big pot without getting sucked out on (who dosen't), $3 is the minnimum you should be betting on that flop.

As for the turn, you now don't know if their responding to your weak flop bet, thinking you missed, or have hit 2pr+. Leading the turn is a strange line (most monsters would ck-rs) so I'd probably call this down to mimimise losses against a big hand and maximise value from a bluff.