Comment 9 for bug 1074779

Causing the problem on Ubuntu 12.04.1 when installing the 3.5 kernel is not too surprising as that kernel contains some, but not all, of the updates needed to support your hybrid graphics. All of the pieces are supposedly present in Ubuntu 12.10, as per bug 1053250 (it doesn't mention the nouveau driver but I recall reading that it was upated to support hybrid graphics too), however hybrid graphics is only working for a select few people (such as the reporter of bug 1053250, who has different hardware to you) and remains problematic - see http://www.phoronix.com/scan.php?page=news_item&px=MTIxOTM
This article also summarizes some of the hybrid graphics improvements planned for Ubuntu 13.04. See https://blueprints.launchpad.net/ubuntu/+spec/desktop-r-gaming-platform-graphics-support and especially https://blueprints.launchpad.net/ubuntu/+spec/desktop-r-hybrid-graphics-user-experience to monitor progress in this area.