IELTS general writing task 1: Please help me check this letter

You live in an English speaking country and you want to do some voluntary, unpaid work in a developing country. Write a letter to a company called Cultural Expeditions, which organizes such trips. In your letter:
• Explain why you want to do the voluntary work.
• State what your skills and experience are.
• Indicate where you would like to volunteer and for how long.
Begin your letter as follows: Dear Sir / Madam
You should write at least 150 words. You should spend about 20 minutes on this task.

123 George Street,
Randwick, NSW2031,
Australia,

September 12nd, 2014

The Director of Cultural Expeditions
St. Paulo Street
Washington D.C
USA

Dear Sir and Madam,
I am writing this letter to apply for the vacancy of English teacher as a volunteer for children in rural areas in Vietnam for two months which has been recently offered in your website.

Vietnam is a developing country which have been facing a lot of educational difficulties. especially in rural areas. Thus, in revelant with the mission of your organization, I would like to take the work as an English teacher in order to assist disadvantaged children approach to not only supplement knowledge but also skills needed for their future. Furthermore, I am very keen on explode culture and expand knowledge as well as improve my personality and skills.

I am a senior student of Linguistic major in Washington University. However, I have a keen on teaching children and social activities. That the reason why I became a member of Voluntary Young Teacher last year, a non –profit organization, to help people in difficult situations. A couple years ago, I achieved an opportunity to undertake a two-month project of teaching children in Affica that helped me broaden my experience as well as sharpen both my personal and interpersonal skills.

Should you please call me for an interview, I am glad to give you any further information you may require.

Yours faithfully,
Katy Morrison