Calendar

is there a way to use google calendar in the default calendar app?
while running the app i open settings>accounts, there are only two options 'hotmail & exchange'.

Not really , see this thread.

http://www.eightforums.com/browsers-mail/30742-how-sync-google-calendar-my-windows-live-mail-ca.html#post275167

It'll work from Google -> win Calendar , but you won't be able to update google by putting appointments in your Win 8 calendar , it's only going to work one way.