Can I upgrade from 10.6 to 10.7 for free?
Apple's policy is that you get an OS upgrade for free as soon as the launch date of the new OS has been officially announced. For Lion, this was after July 21st. However, as you discovered yourself:


  Remember your completed order must be entered within 30 days of the date of your purchase of a qualifying computer.


So no, you won't be able to get anything from Apple's up-to-date program, which is the only way to get an OS upgrade for free.