GUI change needs a full software flash and some editing... not to mention a compatible MBUS/FBUS data cable to upload the new flash to it (not an easy job, you really need to be able to code confidently as you'll b0rk the phone if you mess up as MBUS/FBUS talk direct to the EEPROM (main software of phone)).
Ringtones and wallpaper are the same... you'll need a data cable. If thats the same phone I think it is, you should get a cd with the phone in the box which has the software needed to download things to it... look on ebay for a compatible data cable or seek elsewhere on the internet, somewhere may be selling them cheap. From ebay, you'd be lookin at about £10 inc delivery... from a shop, expect to pay about £15-20 (not sure of USD conversions).
EP, glad to see you come back and tidy up...did want to ask a one day favor, I want to enhance my resume , was hoping you could make me administrator for a day, if so, take me right off since I won't be here to do anything, and don't know the slightest about the board, but it would be nice putting "served administrator osnn", if can do, THANKS