Do I get to roll an extra dice for the secondary attack as well??

Opportunist triggers once per attack, not once per turn.
If you had a way of clearing stress between them, then yes. Otherwise, no.

no, you will get a stress token after the first attack and then not be able to use it on the second attack because you have a stress token

Thanks yeah its is pretty self explanatory BUT if i can clear the stress as i was thinking about wingman but once i actually re read it, it clearly states at the beginning of the combat phase..