Welcome aboard glad you joined us.

IMO
You need a good Protein Skimmer, and if you are going to keep coral you will need to upgrade your lighting. If you know what kind of coral you would like to keep then the folks here can suggest lighting options. The only other thing I can suggest is research every move you make before doing it. The biggest mistake made by newbe is impulse buying and failure to research. The time you spend researching will pay back 10 fold. Here at CR you have access to a lot of post with great information. If you do not find an answer there then post a question and/or drop into chat and ask your questions there. We are here to help each other.

Best of luck with the addiction