L1A | Changing Jobs

Hello, I am from India, in software and right now working in the US with a L1A which is valid till mid 2012. I believe there is a good likelihood that I'll be posted back to our India operations somewhere in April 2010. However am eager to stay in US and subsequently apply for a Green Card. Please let me know what can be the likely options. Also am curious to know if I can apply for a GC or does it always need to be sponsored by my company? What is the time that it can take to get a GC in my case and what can be the cost? Am based out of Chicago. Thanks, C.

what does this have to do with Canada?