Thanks Manoj for your query.
Since you are primarily working in Windows environment you need to start something in Microsoft Platform only. The upcoming demanding areas are virtualization, 64 Bit computing, Cloud and grd computing, ERP, security etc. You can learn about SAN and NAS environment, Network Management tools also. As far as ERP is concern you can go for MS Navision.
For any IT company certification gives you extra edge but you should have knowledge of your certification area also. Everybody knows that getting a certification, especially in MS area is quite easy. You have lot of dumps available on the internet. So get the real knowledge and then back that up with certification. Try to install and configure servers like windows 2008, exchange server, Domain server. Get the theoretical knowledge as well as practical knowledge of the same. If you are interested in security area go for CISA certification. Learn about firewalls, security policies, security devices.
So there are many area for you. Start from one area and learn as much as you can learn in that area. Be focused on that area only for some time. If you feel you have mastered that then move to another area.