godaddy subdomain used as FQDN on my centOS7 w/cwp

I wanted to know if this can be done. I have few domain names reg. with Godaddy. I bought a shared VPS ( Linux + cPanel ) for one year, and it just sucks slow etc. You guys know. What I tried but Im sure that its more settings than just a simple subdomain.mydomain.com DNS ZONE RECORDS having that sub-domain-name point to my WAN IP address. and I pointed the servers local LAP IP and PORT number to the WAN IP address on my Home ROUTER.

1.) Should I use godaddy Name Servers ?

2.) Is this even something that could work ? So far I got it to work that when I enter subdomain.mydomain.com it goes to the WAN-IP and PORT opening up the CWP admin panel.

3.) From here on I'm totally new to CWP Im not some linux guru but I have been using Linux and  understand the LOGIC for file structure the Directories, etc. Im not sure what to do next. so far I have not got passed installing the MOD security.

4.) last but not least my Godaddy VPS goes down in 8 days. I know one thing that godaddy or 1&1 services suck ! Im just trying to host my own domain from home and keep learning and trying new open source CMS, Portals, etc

Can Someone Please give me some advise.