Can someone correct this letter for a post of au-pair? Thanks!

Dear Sir/Madam,

I would like to apply for the post of au-pair on summer 2013. My name is -first name surname- and I am nine-teen years old. I live in -my town-, a town which is really close to Barcelona (Spain) and I study first course of journalism and political science at –my university- in Barcelona.
With regard to your requirements I believe that I am a suitable candidate for this post as I have experience in working with children because I have been a volunteer at the children hospital X since summer 2010. My job there consists in making the children’s stay nicer by playing with them in the games room or in waiting rooms, I also stay with children in their own rooms while their parents cannot be there. I love volunteering, it makes me feel useful and I receive more than what I give. I think it is really important to give something to society, if everyone gave something without expecting anything in return world would be a better place to live, although it is just utopian philosophy. I have also worked as a babysitter looking after my mother’s friend’s son.
I believe my English level is good enough for the post; I have the qualification of the Intermediate Level of English by the Spanish Official School of Languages, which equals the First Certificate of English in Spain. I took this certificate two years ago and I have improved my English level since then, although I have not had the chance to get a higher certificate, I am preparing to get Advanced Certificate next year. In high school, I got the Qualification of Honor and I was the best student in my class. In Selectivity, the entrance examination to college, I got a 9’1/10, which was the higher mark in my town and I received a Distinction of Honor, which is given by the Catalan Regional Government to best students in Catalonia, those who have an over 9 mark in Selectivity. I made a great effort because I needed a high mark to enter my university, mine is one of the most prestigious state universities in Spain and I knew I had to study journalism there. Journalism is my passion and I want it to be my profession, I have always been certain about that. I know the employment status in journalism is not living good times but I also know I could not do anything else, and that is why I am also studying political science, because this way I will be journalist who is specialized in politics. I am really interested in politics; I read the newspaper and listen to political talks on the radio every day. In addition, although I am still in first grade of journalism, I have interviewed two important Catalan politicians.
Apart from that, I love reading novels, specially the historical ones –history is one of my passions– and also classic literature. I also like writing, I have written stories and poems since an early age and I used to win writing competitions at school every year. On summer 2011 I wrote a historical novel about Spanish Civil War and post-war period in Barcelona and it won a local competition. Now I have not written any story or poem for a long time because since I am in college I do not have enough free time. However, at hospital I sometimes tell children stories I invent and they like them a lot. One of my dreams is to see my name on a book cover. And another of my hobbies is cycling; I am really conscious about the environment and that’s why I use my bike to go everywhere. Here in Barcelona it is not as common as it is in other European cities and I think it is a pity.
I live with my mother, my stepfather and my grandmother, I do not have brothers of sisters but I do have a stepbrother and a stepsister who are children my stepfather had in his previous marriage. They live with their mother in another town and I do not see them much often and it is a pity because I love them as they were my biological siblings. When they were younger, they used to come to my home on weekends, but now my stepbrother is 18 and my stepsister is 14 and they do not want to anymore. I would love to see them more often because they are my family. I love animals, although I do not have any pet, I would like to have a dog or a cat, but my grandmother does not like animals, so I cannot have any pet. However, my aunt has two dogs and when I go to her home I play with them, I will never be old enough to play with pets.

So this is me. I hope you think I am appropriate for the post.

Yours faithfully