How should I improve my practical payroll knowledge? Would be an ideal for me to change into HR field?

Hi All, I am working with Chemical industry from last 2 years as Executive Assistant to Director (Technical) Prior to this i have 2.5 yrs of experience in HR (Liasoning) not in Core HR . I have completed my MBA in HR ( 2011-13). I would like to work in Core HR like: Recruitment & Selection, Training & Development , Organization Development, Payroll, Policy Recommendation,Salary and Benefits, Employee Relations. I have resigned with my current company just because i m getting frustrated with my profile. While applying for HR position no one is ready to hire a fresher as everyone would like to have experience person for HR. If they agree to hire than they offer me the half of the salary which I am getting right now. I have excellent administrative skills, ms office etc. There is only one drawback; I don’t have a practical knowledge of HR

Would be an ideal for me to change into HR field? Or Should I continue in admin or as Ex. Asst. in other company?

How should I improve my practical payroll knowledge?

Dear Manan,
There is no need to go in the field of EA again as you've taken the decision of leaving that field for better growth and your interest in HR. However, you'll have to start again as a fresher in HR because you currently don't have experience required in HR. You've to compromise in salary for a year. Consider 1 year as your training period and learn as much as you can by gaining practical knowledge with working in company. No books or institute can provide you the practical knowledge. With the skills and degree you've, I am sure that you'll reach the salary and designation you deserve sooner or latter. But, yes initially, you''ll have to compromise on salary part.
Regards,
Manish

At the Outset really apologies for the late reply, Well,Thank you so much for your Kind Advice on the above subject. Indeed, a lot I need to learn by gaining practical knowledge with working in company.
I really appreciate your guidance !!!
There is one more thing i would like to ask you that My Current Company where i going to resign next month, they will give me the Experience letter mentioning my position as an EA (EX. Asst to Director) .Will it be good for career in Future.

Dear Manan,
Experience letter of EA to director will not be much useful in HR but atleast you require it to show it as a proof to your future employer as you'll mention it in your resume. But, the experience will be handy if you're getting the profile of HR & Admin, in that case that experience letter will be added advantage for you.
Regards,
Manish