You may wish to consider the MCITP: Windows 7, Enterprise Desktop Support Technician. This certification requires you to pass 2 exams: 70-680 (which will give you the MCTS on Windows 7 Configuration) and 70-686, which gives you the MCITP.
http://www.microsoft.com/learning/en/us/certification/cert-windowsclient.aspx#tab3
There are no other prerequisites for sitting these exams, except of course for having the adequate knowledge. The two years of experience that you have in this role can be perfectly adequate, even if the exam description for 70-686 claims that
it is targetted to people with three years experience. But this is only a suggestion, not an absolute requirement. Only one year of experience is suggested for 70-680 (MCTS).