You can not extra increase your phone volume its set by phone companies you can not increase.
yep, that's where i got my super loud one. 1+ for zedge.correct. You can though download ringtones like from the app "ZEDGE" from the market. Some of their ringtones are louder than the stock ringtones. I am sure it all is in the file makeup but they are indeed louder. (not all but some of them)