../admin page, it shows me the login page directly instead of create your account page. I don't have any account for Craft so I'll definitely need to create an account of mine in Craft but not able to find the Create Your Account page.
You or the person who setup your system created an user account. See step 5 in the installation documentation (http://buildwithcraft.com/docs/installing). Therefore there should be an account and you could try to reset the password.
If you have access to the DB directly you could get or set the email/username associated to that account. Another option would be to start with a fresh installation.