I have a problem with my itunes?

I plugged my phone into my computer and like usual, itunes popped up. I have been having a problem with my phone. First when I got the new update for my phone, it deleted all my ringtones. So i purchased a new ringtone and in my ringtone setting, it said that the ringtone I had just purchased was my default ringtone. But when people call me, it plays some funcky tone that is part of the phones tones. My boyfriend said that I should hook up my phone to itunes and put it on the itunes. So I went onto my itunes and clicked on the iphone link in the top right corner next to library and now that has disappeared! Please help! I seem to just be ruining everything instead of fixing my problems…

Added (1). I know about the free ringtones. My boyfriend has a bunch of free engine sounds as ring tones which is pretty cool. My problem is that I purchased a ring tone. It says that it should be playing if someone calls me but it doesn't and I can't find it on my phone. It is annoying that I did buy this ringtone but it will not play on my phone or even show up

There are lots of great Ringtones you can get for free simply by searching the web using your phone.
Just do a search for 'Free Mobile Ringtones Download'.
I downloaded 10 great ringtones which means I can keep changing my ringtone if I get tired of one.
If you want to download a ringtone from ITunes just do a web search for ITunes this way you can download what you want direct from ITunes.