I am no expert in this but I did have a fairly serious play with IR a couple of years ago. My experiences are in these threads.
http://www.worldphotographyforum.com...ead.php?t=4494
http://www.worldphotographyforum.com...hread.php?t=63
I have taken the liberty of running your first image through the Khromagery action in CS2 and attached the result. For that action go to this link
http://khromagery.com.au/digital_ir.html
and you can download the action from the resource page. Also attached is a quick B&W version.
Looking at your image it appears very grainy, and from my experience suggests it was taken in jpeg. I found a significant difference taking in RAW then converting to 16 bit Tiff before running the action. Again I have attached a comparison 8bit v 16bit for you to see.
All my IR was taken on a circa 2002, 6mp D100 so grain wise I would expect your results to be similar or better.
Don