How can I install ubuntu 12.04 besides ubuntu 13.10

I have ubuntu 13.10 installed in my laptop (lenovo u430) and I want to have ubuntu 12.04 also (because of graphic drivers). When I try the live cd, it says I have no other OS in my computer and that it'll erase the disk. If I try to resize the partition (lvm) I can only reduce it in 50 MB, but I have around 300 GB of free space. Is there any way around these problems?