Proszę o sprawdzenie - LETTER OF APPLICATION

I am writing to apply for the position of on the position the helper on information desk which was advertised in Wednesday’s edition of the Morning News.
I am twenty years old and I graduated The economic technical school in Warszawa in 2007 with title Technique of the Economist, specialist: the book-keeper. I hold the certificates in using computer and word-processing. Now I study in College in Poznań. I speak fluent English and some German.
I have been working as a the helper of the book-keeper at in the Provincial Office in Poznań since May 2007. Prior to this I spend two months as a salesman of clothes at the shopping centre in London.
I am friendly, organized, patient and work well under pressure. I think that my candidature is the best and I will perfectly manage on this position.
I enclose my CV and I would be glad to attend an interview at any time convenient to you.

I am writing to apply for the position of 'on the position' (niepotr) 'the' A helper...
I am 20 years old and I graduated FROM The economic technical school in
'Warszawa' WARSAW in 2007. I OBTAINED w'ith title Technique of the Economist' (to dla mnie wyglada bardzo dziwnie), specialist: book-keeper.
I hold the certificates in using computer and word-processing (ale np jakie?). Now I study in A College in Poznań.
I have been working as a 'helper of the book-keeper' (lepiej Book-keepers assistant) at in the Provincial Office in Poznań since May 2007. Prior to this I spenT two months as a 'salesman of clothes' (clothes salesman) at 'the' A shopping centre in London.
....I think that my candidature is the best and I will perfectly manage on
this position.... (dla mnie to troche niegrzeczne - troche wyglada na 'boasting').