My Present Situation

Hello, my name is Yu Er. I’m 25. I graduated from Shandong Normal University in September, 2010. I have worked in an industrial equipment manufacturing company during last three years.
The company I work for is a private enterprise. My boss is an old man, though he doesn’t think so. He is a good person and a good manager. After three years in the company I find there is no challenge in my job, so I want to change my job. I want to have a new life.
I work there as a buyer. The first thing I have to do in my job is looking for the suppliers of the main raw materials. Statistics about the quality of the materials and enquiring about their price is the thing what I am doing everyday. The life there is easy but hopeless. Now I’m ready for a new life.

You could say either "The company I work in," or "The company I work for."  Both are acceptable but we would normally use the second term. Than is used for comparisons, i.e., "I am taller than you."

We usually spell out the smaller numbers. Try to keep the tense consistent throughout a sentence or paragraph.