I am interested to improve understanding related to Research Methodology so please suggest a comprehensive book of research methodology for the preparation of comprehensive viva.
I agree with Daniel Wright. Although there are some common elements belonging to "all scientific activities", the methodological choices depend on several factors, in which disciplines and research topics will bring variation. One can say, that disciplines and departments or even professors maintain "cultures" of their own and methodologies are essential parts of them.
Instead of single methodological issues, the processes and dynamics of writing and other forms of scientific communication may be more useful to familiarize oneself with first. Practicing information searching about your discipline will familiarize you with the relevant methodological trends, fashions and debates.
I agree that it varies by discipline, but since you are in an applied social science field (TESOL), I recommend Creswell as an overview, Research Design: Qualitative, Quantitative, and Mixed Methods Approaches. Two other comprehensive textbooks in this area are by Babbie and Schutt.