Mr Sharma said the upgrading of CMAG was of "tremendous significance" and would enable the group to engage earlier and more constructively with countries heading towards a breach of Commonwealth values.
"There is agreement to lift the bar," he said. Mr Sharma was reappointed for a further four-year term.
But ahead of the final session yesterday the group's chairman, former Malaysian prime minister Abdullah Ahmad Badawi, warned that the plans for a stronger CMAG were not sufficient and that the summit risked being remembered as a failure.
Under the programme outlined in the final communique, both the evaluation of the proposal for an independent commissioner and the text of the proposed charter will be presented to a meeting of Commonwealth foreign ministers in New York next September.
Many of the proposals of the controversial Eminent Persons Group were adopted, or placed on the New York agenda.
Chogm adopted 30 of its recommendations "without reservation", established a task force of foreign ministers to provide more detailed advice for New York on a further 43, but deemed 11 others as "inappropriate for adoption".
"In short we have done and delivered a lot," Ms Gillard said. "Some of the discussions were not easy."
The meeting refused calls to drop Sri Lanka as host for the next Chogm because of alleged war crimes and human rights abuses, and let slide calls for other policies such as the repeal of anti-gay laws and legislation hindering the fight against HIV/Aids.
There were positive moves, such as the creation of a body to advise and monitor elections and a clear focus on key issues such as food security and climate change.
Plan International Australia also welcomed a commitment to implement international accords on women's rights, and to promote measures to tackle early and forced marriage.
Chief executive Ian Wishart said the move would boost global efforts.