This one has always been a bit of a handwave because Linked powers need to have the same range. By the book, with just the main book, you'd have to set up either Healing with the Reaction extra triggered by damage (or Triggered as long as your concept supports preparing the healing ahead of time with actions, and having your prepared healing able to be "disarmed" with skill checks) or Regeneration with a Limited (Source) Flaw so that it only works if you've done damage recently.
Outside of the main books, one of the Power Profiles did introduce Psychic Vampirism, which is a handwaved Linked as follows:
You mentally drain the target's vitality to replenish your own. Some Psychic Vampirism is also Insidious; the target does not feel or notice its effects until incapacitated by it. If the series features lethal damage, then draining targets past incapacitated leaves them dying. Psychic Vampirism able to heal Damage conditions as well as fatigue has a +1 modifier (removing the Limit on Healing). Psychic Vampirism requiring you touch the target has a -2 modifier.
Psychic Vampirism: Perception Ranged Cumulative Affliction (Fatigued, Exhausted, Incapacitated), Resisted and Overcome by Will, Subtle, Linked to Healing, Subtle, Limited (Energizing Only), Limited (Self Only) • 2 points + 4 points per rank
Rule 0 being what it is, to do whatever is the most fun, discuss it with your GM and see if they'll go for how you propose the power would work. Or, if you're the GM, use it. Just remember that anything the player can do, the GM can do, and potentially vice versa. And if you're the GM, and you're putting this on an NPC, and you forbid PCs from taking it, possibly because you feel it would be too powerful, consider whether it's just a form of GM Fiat and therefore something to pull for a Hero Point rather than as a discrete power.
"As you go to strike the bruised and bloodied Madame Nefaria, she stabs a dagger glowing black into your side. She rolls a 17 and hits. Roll a Toughness save. Ooh... looks like she's Staggered you and inflicted a -1 penalty. Take a Hero point as she heals the same due to her vampiric nature. Madame Nefaria's bruises fade as she laughs evilly and yanks the blade out of your side, her movements no longer pained and jerky."