Upgrade your NB's as far as you can, then just patrol them with the entire group. Yes it will be painful with all those cruisers, but I think you will prevail (even if your NB's will be severely damaged as well).

If this is an emergency adding some planes to Naval Bomber stack should be able to kill it already. If not upgrading NB or spamming out 10 subs should be enough.

Cruisers with level1?

I would go for a combination of the earlier recommendations. They only have two destroyers so will be slightly vulnerable to subs. If you can spam a stack of subs to lock that stack in place in melee, you can patrol your naval bombers over them as well. Upgrading your naval bombers will both increase their combat effectiveness but also increase their range to give you more flexibility in bringing them to the fight.

If you have the time and resources to upgrade your naval bombers that would be preferred. One trick to doing that is to upgrade them two levels at a time. Start an upgrade in the window of before your research for level three will finish making sure your upgrade will end after the research does. This way you’ll pay to upgrade them to level two but will get level three units. You will need manage your resources carefully to know exactly how much you need to have on hand during this window for the upgrade.

Submarines. Dozens of them. I caused havoc to enemy ships with my subs. Two destroyers ain't enough to stop dozens of of subs. But once again since you only have naval bombers, use them. Another more expensive option would be to just nuke it. Guranteed destruction.