Thank you letter to my boss

I was working at a car dealership as the lease terminations manager for a while..when i first started i knew absolutely nothing. Now i'm moving on (in the same industry) to something bigger and better. I just want to thank my boss for giving me the chance to work at such a great place where i was able to learn and apply what i learned towards my new job. I just feel that what i wrote is too dry.

here's what i wrote.

Dear Lydia,

I would like to take this opportunity to express my heartfelt thanks to you for giving me the oportunity to work at Gus Machado Ford. I really appreciated the time that I spent working with you on both a professional and personal level. I certainly learned a lot about the unique aspects of customer service and sales in the car industry.

i wish you, the department, and Gus Machado Ford continued succes.