Increase the point size in a plot

careisin

I'm using Rapidminer studio 6.4 on a Window 7 machine. 

I've created a density graph after doing a k-means cluster analysis on it.
X-Product Category
Y-Product Retail Cost
Point Color-Product Cost to produce
Density Color-cluster

The graph conveys everything I want to show (which is a lot on one graph). The problem I'm having is that I would like to increase the dot size for the Point Color.  It is so small, it is hard to see the variation in the scatterplot. 

I've seen some posts about modifying code, but I'm new enough, I don't know where to access the code to do something like that.

Thanks