Bitbyte, I would see your best asset to move ahead right now in the IT field to be your 10 years of experience. The Comptia certs especially the A+, N+ will round out a resume nicely. Obtaining your Cisco certs, would also help. There are many resources to help you get your Cisco from places like this.
Since you are a Linux/Windows admin certs for those OSs will probably be the best ones for you to look towards. On the Windows site you’ll want to look towards the MCSE for Windows 2003 or the MCITP for Windows 2008. Most Linux distros have certifications from the vendors.
I wouldn’t recommend recommend Cisco certs for you unless you work with Cisco gear on a regular basis, or unless you want to move into networking.