@Janet
I feel your pain, and you have a fair question for Apple. Unfortunately Apple, in common with many software companies, can't distinguish between a problem you have with their 'perfect' software, and a problem they have caused you with what is really most imperfect.
As I remarked in my first post, I found a fix for this dated April 2010, so it's been going on for a long time without Apple ever fixing it. And it isn't just Win 7 64-bit it affects; it's every WinOS, AFAICT.
And no, it shouldn't be necessary for you to get down and dirty with Windows Explorer to deal with this, and yes, Apple should release a version of iTunes - specially if necessary - to address this.
But unless and until they do, I'll repeat my recipe for how you fix this; though if what you really want is to rail ineffectually at Apple, rather than make the problem go away, I guess you'll prefer to ignore it.
The probable reason you can't find the file is that on Win 7 64-bit, you have to look in C:\Program Files (x86)\Common Files\Apple\Apple Application Support, and copy (NOT move) the file to C:\Program Files (x86)\Common Files\Apple\Mobile Device Support.
As I said; it's Program Files (x86) on 64-bit WinOSes, but just Program Files on 32-bit ones.
If you sprang for that $50, you certainly wouldn't get an upgraded iTunes; at best an Apple tech might reach out to your machine and do the above, assuming (s)he knew what the fix was.
Bite the bullet and look again; if you aren't comfortable copying files yourself, find a friendly techie to do it for you.
And whatever is left over from the $50 after that, you can spend on nifty tunes from the Apple store :-)