I had a judgement filed against me over ten years ago and never knew about until I received a renewal of judgement from the court a few days before it expired. I contacted the court into filling the proper paperwork to fight it and they stated that I cannot fight it because it is a renewal. Now I am receiving a subpoena to go to court about this, I live in California and want to try have all my ducks in a row and be able to have the judgement reevaluated and lowered. What do I need to do that.

Consult with a California-admitted attorney and double-check that what (the clerk, I assume) told you that there is no way to get the judgment quashed.