A correction if I may... I tried to read all the posts, but have to leave.
I am suspecting you do not actually have the full Photoshop version. Those are now CS4, CS5, and CS6. Instead I think you have Photoshop Elements 9, which is a lesser version of full Photoshop.
Not that that makes a big difference for many of the responses, but it will help somewhat if you make that distinction when you ask about it. PSE9 would have run under $100, while any full version of PHOTOSHOP would have cost at a minimum with an educational discount about $300. In it's full retail pricing it is about $600. That, I mention only to help you make the distinction.
That said, PSE (elements) will do about 97.5% of what the full Photoshop, such as the current CS6 will do. It's just that it's so much cooler to say, "Well, I use CS5 or CS6!!!"
Naturally because of the price difference, the full photoshop certainly has some features for very advanced photo manipulation and professional use. However, Elements is no slouch, and will certainly do the tasks you are after at this point.
Probably my biggest point here is that you will get more appropriate answers if you refer to it as Elements. Furthermore there is a dedicated forum that will give you even more direct answers. It is
www.elementsvillage.com. It even seems to be monitored somewhat by some very technical Photoshop Elements people.
So, my suggestion (and it is only a suggestion) is that IF you have PSE 9.... you would be ahead to refer to it as Elements 9, and drop the reference to Photoshop. If you were to sign up for some full Photoshop (CS..) classes, and you in fact have Elements, the classes would be useless for you.
Just my nickels worth if you have not already made the distinction.
Element is a worthy and capable product.
And as you are finding out, most of the references to Plugins will lead you down a path to much more $$$. The people who take the lead from Adobe and write these plugins, must be laughing all the way to the bank. I would bet someone could show you how to do what you want to do with JUST the Elements program.
I have never paid for or used a plugin, but I am not a real fan of Post Processing. I prefer to take pictures that don't lead me to a chair in front of a computer on a sunny day, when I could be outdoors with a camera.
Good luck.