Hello Ritesh Kumar Singh,
Congratulations!
And Welcome to CodeRanch!
The next certification totally depends upon what kind of work you are doing, or want to do.
If you are interested in Servlet/JSP, then WCD is really nice certification (nowadays they also cover JEE 6 version).
If you are quite serious about core JEE technologies, then you can go for EJB certification, but in my opinion, doing WCD followed by EJB (and JPA if you want) would give you pretty broader view of enterprise application (which might come in handy if your long term goal is to do enterprise architect certification).
But if you are interested in Core Java, then natural upgrade would be OCMJD exam.
I hope this helps.
Regards,
Anayonkar Shivalkar (SCJP, SCWCD, OCMJD, OCEEJBD)