One thing you could try for better results is to set a custom white balance with the filter attached. If you do that (and if it takes) you might get a better effect on the foliage. If the custom white balance doesn't take you can try upping the expose and setting again. If that doesn't work than you may need to do what I do. Shoot RAW and set the WB with Rawtherapee. I shoot Nikon and CaptureNX2 sets the WB perfectly but costs $130. You can try the demo.
If you want to shoot infrared and get the colorful effects you would need to have your camera modified to do so. The internal hot mirror filter on the sensor is keeping you from getting the pretty white foliage. Also with a 720nm filter you don't get a whole lot of color in the sky, it is nearly the same as b&w. As jerryc41 stated earlier, lifepixel will convert a camera for you but with most of the mods you won't be able to shoot in visible light.
I have some examples of a 590nm internal filter here: http://www.uglyhedgehog.com/t-134209-1.html
I did a little research and some math. I found that shooting (S) quality in either RAW or JPG reduces the size to 4.5 megapixels. This will give you an 8x10 print of about 200ppi. While acceptable you may want to consider using the (M) mode which will reduce the size to 10 mp (RAW) and 8mp (JPG) and allow you to print 8x10's at about 300ppi.
What OS are you running and what version of WD software do you have installed? Also you could type [systeminfo] without the brackets in the command prompt and paste the results. I'll try and help when I get back from dinner.
I prefer to shoot at the highest quality but I do large prints from time to time. I feel it's better to have all of the data available. Shooting in (S) lowers your pixel count by 1/4 according to Canon's website. (Your print size is not reduced by 1/4 though)
Taken through an Orion Astroview 120ST and D3100. I had set my telescope up at a park so everyone could see. Snapped this quickie photo when people weren't around. The blurry spots on the sun are sunspots!
Taken through an Orion Astroview 120ST and D3100. I had set my telescope up at a park so everyone could see. Snapped this quickie photo when people weren't around. The blurry spots on the sun are sunspots! :-o