I think I may have given my mouse a renewed lifespan. I just hunted around on the Microsoft update site to see if there were any recent mouse driver updates and found one for this mouse. After downloading and installing, my mouse has lost the skittish personality it had developed in the last week.
If it lasts, hopefully I won't need to replace it so soon after all.
I took a look at those on Amazon too, Tsar. Thanks. I'll keep links to them for when my mouse finally bites the dust.