I'm not totally clear on what you are asking. In general though the idea is:
1) You buy a domain name and set up name servers. The name servers tell anyone trying to find your site where to go to find out (ie.your DNS host, which is often the same as your web host).
2) You then set up your DNS records on that server. If you just need a web site you will have an A record for www that points to your web site. In your case this can be either of your static IPs (it's up to you).
3) You then need to make sure any traffic on port 80 to that ISP is forwarded on from your modem to the server, and allowed through the firewall.
If I'm understanding you correctly your questions are about step 2. Your statement "I am register my domain ... with IP address..." is what's confusing me. You don't register a domain with an IP address. You register a domain and set up your name servers with the domain host. Your name servers will host the DNS zone record for your domain. It's in your zone record that you point web traffic (ie. create the A record for www) to point to the actual IP address of your web server.
Unless you have a very good reason to host this yourself I would strongly consider using a third party web host. Basic hosting from a good host will cost $50-$100 per year. If you get serious traffic or need big databases it might be a few hundred per year. At that cost you can only afford an hour or two of your time before you are better off to go hosted. And that's not mentioning the cost of the static IPs and the two servers.
