IIRC L1 is not transferrable, so your best bet would be to try to snag an H1B at a different employer. It's much easier to do while in the US, so I'd ride out the L1 and apply for jobs between Nov and February to get in the H1B paperwork in for April 1st and hopefully get in the lottery. If it doesn't work on year, rinse and repeat. Depending on your occupation, O1 is a possibility, one of my friends switched jobs and went from L1 to O1.
The alternative if you're not married is to get your GC through your marriage if you have a US partner.