Linux Mint follows Ubuntu's updates to the kernel. So if Ubuntu will make kernel 3.5 available on Quantal / 12.10, it will be available on Linux Mint 14. That said, by default kernel updates are not enabled on Linux Mint. This is a precaution, as kernel updates can break your system and average users wouldn't know how to recover from that. Hence it is not enabled by default. In the Update Manager > Edit > Preferences you can enable visibility of level 4 and 5 updates, or enable them to install by default. Level 4 and 5 updates cover such things as the kernel and xorg.