Not sure if you have seen this site yet.....it's great for creating graphs for all the functions in the course. It's easy to use and easy to put the graphs into word documents. I thought I had gone to heaven when I found it! If you haven't seen it....give it a try!
http://www.padowan.dk/download/
I've used that program before and it's really quite good. Very simple interface.
Another good graphing tool is www.desmos.com. It's fextremely useful if you want to make sliders. For example, if you wanted to show students what the variables do in y=a(x-h)^2+k do, this is a fantastic choice. You can quickly and easily make sliders for a, h and k and move them around to see what the effect is on the graph. Also, it's also all online so you don't have to download anything to use it.