If you donate 10 BTC, you can get a special "Donator" title and a green "who's online" color. If you donate 50 BTC, you get VIP status and the ability to create a custom title for yourself. Both Donators and VIPs also get access to an exclusive forum section.
Changing your name won't be possible unless you donate 10 BTC ( i believe ), or have a very good reason for theymos to do so.
Since you're currently a Jr member, it would probably be better to start a new account instead of going through that hassle ( or pay 10 BTC), as it most likely isn't worth it.
By doing this, you plagiarised, which seriously violated the forum rules. So before you get ban by moderators (I don't hope so, but you might be banned); I give you this topic to read
Unofficial list of (ocfficial) bitcointalk.org rules, guidelines, FAQ
Please read all of them if you have time, if not just focus on the rule #33.