A $20-$40 game. You are in the small blind with the A-5. An early player limps and an elderly lady in middle position limps. She is a tight-passive player that only bets or raises when she thinks she has the best hand. But she will faithfully call to the river with any chance of winning just to see who wins. You limp. There is $80 in the pot and four players. The flop is: A-8-6, giving you top pair, no kicker and a backdoor nut flush-draw. You bet. The big blind folds and the early player calls. The lady raises. What do you do?