First congrats on a nice reader. I capitulated and bought a 3rd Kindle because I got a great deal on my newest K2i, $159 new from Amazon after my new Audible subscription. I like it well enough. And, well, not gonna find a reader for that price anywhere that is as nice as the K2i, not today anyway.
Something I found made a huge difference was using the K2i
Font Hack and switched to the Helvetica font over the default K2i font...made all the difference, had I been forced to read using the default font, I would have just turned around as sold it for the $120ish profit then used the cash to by a Pocketbook reader instead...but the Helvetica makes it a nice reader now.
But Google "kindle font hack", you will need to decide if it's right for you but once you try the different font options (it's tedious as one needs to uninstall the previous hack before trying a different one) you will be surprised at the difference in clarity.
Oh, I believe your K2i is likely running firmware version 2.3 (newest firmware). And the install stuff is pretty easy and you can do it "cookbook" style just following the instructions like reading a cookbook.
Here is the page with the fonts and instructions as well as sample images to show the differences even before trying it out:
https://sites.google.com/a/etccreati...kindlev23fonts
There is a thread here with links to the font hack as well, I would post the link but am between laptops until my new one gets here this afternoon and I port everything over. But someone will have it for you if you can't find it.