Do we know where the supernova was that gave our solar system its heavy elements?

All the heavy matter almost certainly did not come from one supernova. What happens is that when a star explodes, it forms a planetary nebula that slowly drifts out into space. Eventually a whole bunch of these cloud-like objects will mix, and separate, and mix, and separate some more, and form what we call molecular clouds. When the conditions in a molecular cloud are right again (i.e. a pressure wave passes over them), star/planet formation can commence again.

Supernova exploded at the center of the galaxy. Of every galaxy. Thats why there is a cluster of suns and astoroids and the rest ofthe crap you find in the galaxies surrounding and orbiting a center. Because it all comes from that center

We actually live in a barred spiral galaxy.  It's possible that structure has somehow collected  free gas and the dust and gas from many supernova explosions, and shunted it out to the outer regions of the galactic disk such as where our Sun is.  It may also be that the spirals of the galaxy compress this matter into giant gas clouds, and nearby supernovas might create shock waves in these clouds to initiate star formation.  These 'stellar nurseries' as they are sometimes called can birth a great many stars.  For example the Orion Nebula has about 2000 times the mass of the Sun and contains at least 700 proto stars.

For this reason, I believe it took a long time before enough heavy matter was collected to form solar systems like ours.  We may be one of the first systems that can support life, though I have no data to support that.

Our Sun is considered a population I star which means it's the third generation of stars.   The heavier elements could be from the death of first generation population III stars or second generation population II stars and more than likely from the deaths of many stars of either prior generations.   I don't think it can be nailed down to one star.

we don't even know where our solar system was 4.5 billion years ago. stars orbit the galaxy at slightly different speeds and sometimes approach close enough to interact gravitationally. it's hard to predict the sun's exact position a few million years ago, let alone a few billion. that supernova remnant could be on the other side of the galaxy by now.

It was not a single star / supernova.  It would have formed from the remains of several other "gone-by" stars.