The labor certificate step along takes anytime between 1-3 years, again, depending upon what region you apply in.
You can go to http://workforcesecurity.doleta.gov/foreign/times.asp
to get some sense of it.
Nowadays, one can combine both steps of 140 and 485. But there is also a risk involved meaning that if either step is rejected there would slight chance to reaplply.
Besides, you MUST stick with your sponsor before your 140 is approved. For example, if you are laid off before I140 is approved your entire application is wasted.
Hope the above will give you some ideas.
Good luck!