This isn't going to work, in this form. You need to be light years away to have an atmosphere survive, at which point the heavy metals enrichment will be insignificant. I can see a couple of different ways to achieve a planet with both life and heavy metal enrichment.
Formed quickly after the supernova
Our solar system was formed from gas and dust that includes remnants from a supernova explosion. We know this because we have heavy metals. If we knew more about exactly how they are formed in a supernova, we'd be able to date the one that formed our heavy metals. For example, we know the relative proportions of U-235 and U-238 on Earth rather accurately. That proportion is slowly changing because they are both radioactive and have different half-lives. If we knew the proportions in which they are formed in a supernova, it would be easy to calculate how long ago the supernova happened.
If your planet formed fairly quickly after your supernova, and developed life quite quickly, it's possible to have a life-bearing planet with a high abundance of heavy metals.
Replace the atmosphere and oceans
The supernova happened, and you're left with a rocky planet orbiting the companion star. It used to be a gas giant, but it got crispy-fried, down to its rocky core. Heavy elements got deposited on it. Everything went quiet for a while.
A few million years later, the star system has an encounter with a stellar nursery and blunders through the Oort clouds of a bunch of new solar systems. Lots of those icy bodies hit your planet, giving it a new set of water and gasses. Life restarts, after a while.
As a parallel, Earth's water has to have been added after the planet formed: it's too volatile to have stayed on Earth during the initial collisions that formed the planet. The water seems to have been added in the later stages of the Late Heavy Bombardment, see the Wikipedia article on Formation and Evolution of the Solar System#Asteroid Belt. So this is just a repeat of that process, on a planet that had been sterilized by your supernova.