Change "Full post before grid" display

I would like to change the display of the full posts before the grid. I understand how to change the number of full posts but would like to change the following in the display:

* Increase the number of words/characters before it cuts off.
* Have the text go completely from left to right. Right now it does not go all the way to the left of the post area.
* Change the size of the image in the “Full post before the grid” entry.

Which files would I need to alter? What changes? Any assistance would be appreciated. Also, if anyone is a designer/programmer and can take on the task that would be awesome ($ of course).