I worked in this Department for 10 years, previously worked at the Department, which is working in the Payroll Department, then 6 years in accountant position.
I worked in this department for 10 years, previously worked in the payroll department, a department that was six years in the position of an accountant.
I work in this department for 10 years. Before working at the payroll departments which are in the Department over 6 years in the position of accountant.