The card says: action: each hero within 3 spaces of you recovers 1 heart and one endurance.

when you roll a "flash" you become: +2 heart

if you roll another one you become: recover 1 heart

So we do not know if we have to decide if we attack with this weapon or take the action.

or can we take this healing action and attack (for one action in total)?

It should be 2 actions, 1 action for the attack and 1 action for the "healing"

But when you attack you can use the "flash" for:

when you roll a "flash" you become: +2 heart

if you roll another one you become: recover 1 heart

ok thanks. that how we played.