I would echo what others have said.
Take the weapons off and lose the fighter and your NPC crew. You're wasting time trying to fight in this thing when you should just submit to the interdiction and get the hell out again asap.
Based on what you're currently able to do, I would replace the heat sink launcher with another shield booster then have Felicity engineer all 3 (and obviously make sure they're all A-rated before doing so). She can only take them to G1 but its better than nothing. The end result in terms of shield strength will depend on which option you go for. I would personally go for thermal resistant as, in my experience, you're more likely to encounter thermal weapons with NPCs and your unengineered 6A shield generator doesn't deal well with thermal damage when compared to explosive and kinetic.
That should give you sufficient protection while you escape.
That said, multiple encounters (one after the other) will wear you down so accessing other engineers such as Lei Cheung (who can engineer your shield generator up to G5 and boosters up to G3) would be useful. His primary requirement is trading in at least 50 markets which you've probably already managed.