Wouldn't it be time for a check/call here? I don't think a bet here has any positive value. The only hand that would call a bet that wouldn't make a bet itself is 77, or if somebody had JJ. Basicly you have a hand that you want to see a showdown with for as little as possible, and a check/call is the only way to do it.

As for poting it to try and drive out the A7, wait until you have NO hand to try and get people to fold, right now you could still make some money on the hand.