You can see if you have a rescue email address by loggin into your account via the 'Manage Your Apple Id' button on https://appleid.apple.com/ and logging into your account. Then click on 'Password and Security' on the left-hand side of that page and on the right-hand side, if you have a rescue email adddress on your account, your will see a reset link beneath the two questions
e.g. from http://support.apple.com/kb/HT5312 :
If you don't get the reset link then you don't have a rescue email address, and you won't be able to add one until you can answer your questions - you will need to contact Support in your country to get the questions reset.
Contacting Apple about account security : http://support.apple.com/kb/HT5699
When they've been reset (and if you don't already have a rescue email address) you can then use the steps half-way down this page to add a rescue email address for potential future use : http://support.apple.com/kb/HT5312