Argument for the Exsistence of God: Part 1

I posted the other day about wanting to explore some philosophical/metaphysical ideas. Then, I realized that I don't have any time to research to support my writing so I thought I would take a more simplified and sometimes comical approach to the subjects. In the time since, I have come up with a pretty strong and simple argument for the existence of God.

First, I'll start with a definition of Evil. Evil describes someone or something that is morally reprehensible, completely selfish, causing harm or destruction.

To find a perfect, tangible example of evil, one must only walk out his or her front door. Somewhere nearby there exists a weed. A plant whose entire existence is self serving, destructive, and reprehensible. Anyone with any experience gardening would have a hard time arguing in behalf of any redeeming qualities of weeds.

From here it is easy. We have tangible and irrefutable evidence of the existence of evil. Evil can not exist without good, just as darkness cannot exist without light. Else what is darkness? The ultimate goal of evil things is to administer pain and misery to our existence. Good seeks
to uplift and bring joy to our existence.

Here's where the discussion kicks in. Is it enough at this point in the argument to say that God exists? We've established tangible physical evidence that evil exists, therefore can we deduce that tangible physical good must exist? Does this argument require an "earthy" example of something that is completely good in opposition to the complete evil that weeds represent, or can we argue that God is the tangible, ultimate good?