In IT certifications are often more useful than school. Try studying for some of the Cisco/MS certifications which look nice on your resume. If you can swing having your current job pay for it, all the better. But telling a potential employer that you really like this stuff and took the initiative to get the certifications on your own is also a big boost.
Also, familiarize yourself with Linux. It's free, you can run it in a virtual machine to make it easy to use without risking wiping out your hard drive, and it's found in a lot of servers these days. Plus there's a huge community out there to help.
Also, get ready for the upcoming "ZOMG we can't get any more IPv4 addresses and need to upgrade to IPv6" flood. IPv6 is simple (and a good reason to learn how to set up a DNS server), but people are terrified of it.
If you go to Hurricane Electric you can kill two birds with one stone - they offer IPv6 certifications (for free) and you'll need to play around with configuring some server-side software that will provide some structure to your learning.