Help me not get stacked with TPTK ($600)

[billyjex]

Online $600 3/6 NL. We are 5-handed, CO and I have $600, Button has about 400. CO is an aggressive TAG who seems pretty solid. Button is a little looser and not as aggressive but can still put me to the test.

CO opens to 18. Button calls. I call in the BB w/ AJo.

Flop is Jd 9c 5d.

I don't have the A of diamonds. What is my plan? I find this the hardest situation for me in NL, w/ a good but not great hand OOP.