Updating to iOS 7 via iTunes? Problems?

I have the iPhone 4. I'm not synced to an iTunes (my original comp crashed and haven't synced it with another because I don't want to lose all my pics and music).
I don't have enough memory to download the new software.

The last time I plugged into another iTunes to update the software, it froze and the only way to getting phone to work again was to set it back to original settings. I lost everything and never got half my music back.

Will it do it again! Is it only doing this because my iPhone isn't synced with that iTunes?

Updating an android phone is easier than iPhone. So give it up and buy & enjoy an android phone. I suggest Sony Xperia Z, Galaxy S4, HTC One… Etc.