Please Help. I am stuck, need help making this sound better. Let me know what you think. Thanks for your help.

Dear Hiring Manager,

I am writing to express my interest in Admin Assistant position with your company. I have several years of customer service experience, which also includes collections, general office, shipping & receiving and a call center environment. I think my level of experience with computers is intermediate; I have worked with PCís and Macís. I currently have experience with Microsoft Office 2003, 2007, and 2010. In addition to this experience I currently hold an associateís degree and working my way towards my bachelorís degree in security and management. My job experiences have taught me how to build strong relationships with all departments at an organization.
Since I have a variety of work experience, which includes working and going to school from home, I have the ability to work within a team and independently, to be very flexible to change, but also has helped me a great deal with time management, and organizational skills.
Now on a personal note I feel that I surpass most when it comes to having a sense of humor and positive attitude. I do not feel these two skills can be taught during training but comes from within. I love helping people and working with my co-workers and I feel this shows in the quality of work I do.

Thank you for your consideration.