Just a couple of things that are still wrong in Ryu's correction (the red bits), and I changed the rest to make it sound more natural.

 

Hello.

I'm going to introduce myself :))
I'm 18 years old and I go to Hokusei University in Japan, but I've been living in England since September! I go to New College, Nottingham to study English :D
I started studying English about 7 years ago, but I only studied writing, listening and vocabulary at the beginning. I started to study spoken English in April of this year. I wanna be bilingual!! But I'm not very good at speaking English yet...
I want to study more... If you can, please teach me English :))

See you,

Hello

I am going to introduce myself :))
I am 18 years old and I go to Hokusei University in Japan. But have lived in England since September! I go to New College Nottingham to study English :D
I started studying English about 7 years ago, but It was just written listening and vocabulary courses. I started studying to Speaking English since April this year. I wanna be a bilingual person!! But, my oral English skills  are still bad...
I want to study more... If you can, please teach me English :))

See you
-------------------
This is better

Hello

I'm going to introduce myself.
I'm 18 years old. And, I've attended Hokusei University in Japan. But I've been living in England since last September where I study English at New College Nottingham.
I started studying English about 7 years ago, but at that time I studied only writing, listening  and vocabulary. I've been studying spoken English since April, 2010. I want to be bilingual but my speaking ability isn't very good yet.
I want to study more.  Can you please help me improve my ability to speak English?
See you, ________________ < put your name here.

Matthew Armstrong is right.  You need to work on sounding a bit more natural. However,
you also need to continue to learn to write English properly.  I know it's very difficult, but
I think speaking with native English speakers (for you) is the best way for you to learn /
improve your spoken English ability.