RN coders? I have questions..

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I have some questions. I have worked for DME company doing medical billing and coding for 5 years now. I just started college to get my certificate in medical billing and be certified(CCS)hoping to eventually work from home. I want to become an RN coder. Higher pay, more opportunities. How do I do this? Once I finish my 1st year and receive my certificate, what do I need to go back to school for? What direction do I need to go? Really confused with this. Do I need to just take the second year of nursing to get my associates?