I am very grateful for any help and will gladly read any links and tutorials you can give me talking about this.
The Arduino site has a good example to start with.
http://arduino.cc/en/tutorial/Graph
I've been trying to make that example more practical, but keep it super simple.
Processing comes with File I/O examples. Choose File | Examples... and poke around.
Others on this forum have shared their helpful projects too, for example:
http://www.negtronics.com/simplot
http://forum.arduino.cc/index.php?topic=185740.0
While those might take some fun out of learning how to write your own tools, using existing tools will leave you a ton of time which you can spend adding features to your Arduino sketch.