I've made a few modifications to the affiliate plugin, one of them being the ability to sort the columns from low to high and from high to low to help with seeing who is the biggest recruiter, made the most clicks etc etc. (no edits to the original affiliate plugin are required)
Just download this zip and extract/upload the file and folder in it to your mu-plugins folder.
(The cl_affiliate_mod.php file goes in mu-plugins root)
Once that's done, you will be able to click on the table headings to sort them from lowest up or highest down.
A column that is being used as the key for sorting has an arrow pointing either up or down depending on which way you're sorting. See the included images for what it looks like in action.
I hope you like it, it has saved me a few seconds going through the long list trying to find who introduced the most members or had the most unique clicks or blog signups.